diff --git a/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/KotlinClientCodegen.java b/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/KotlinClientCodegen.java
index efdb67eb88d..43393ef8827 100644
--- a/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/KotlinClientCodegen.java
+++ b/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/KotlinClientCodegen.java
@@ -1021,7 +1021,11 @@ public class KotlinClientCodegen extends AbstractKotlinCodegen {
                 if ((JVM_KTOR.equals(getLibrary()) || MULTIPLATFORM.equals(getLibrary())) && operation.allParams != null) {
                     for (CodegenParameter param : operation.allParams) {
                         if (param.dataFormat != null && param.dataFormat.equals("binary")) {
-                            param.baseType = param.dataType = "io.ktor.client.request.forms.InputProvider";
+                            if (param.isContainer) {
+                                param.baseType = param.dataType = typeMapping.get(collectionType) + "<io.ktor.client.request.forms.FormPart<io.ktor.client.request.forms.InputProvider>>";
+                            } else {
+                                param.baseType = param.dataType = "io.ktor.client.request.forms.FormPart<io.ktor.client.request.forms.InputProvider>";
+                            }
                         }
                     }
                 }
diff --git a/modules/openapi-generator/src/main/resources/kotlin-client/libraries/jvm-ktor/api.mustache b/modules/openapi-generator/src/main/resources/kotlin-client/libraries/jvm-ktor/api.mustache
index bdff63a1980..5d00194376d 100644
--- a/modules/openapi-generator/src/main/resources/kotlin-client/libraries/jvm-ktor/api.mustache
+++ b/modules/openapi-generator/src/main/resources/kotlin-client/libraries/jvm-ktor/api.mustache
@@ -63,7 +63,7 @@ import com.fasterxml.jackson.databind.ObjectMapper
                         formData {
                     {{#formParams}}
                         {{#isFile}}
-                        {{{paramName}}}?.apply { append("{{{baseName}}}", {{{paramName}}}) }
+                        {{{paramName}}}?.apply { append({{{paramName}}}) }
                         {{/isFile}}
                         {{^isFile}}
                         {{^isArray}}
@@ -81,7 +81,7 @@ import com.fasterxml.jackson.databind.ObjectMapper
                         {{/isArray}}
                         {{#isArray}}
                         for (x in {{paramName}} ?: listOf()) {
-                            append("{{{baseName}}}", x.toString())
+                            {{#isFile}}append(it){{/isFile}}{{^isFile}}append("{{{baseName}}}", x.toString()){{/isFile}}
                         }
                         {{/isArray}}
                         {{/isFile}}
diff --git a/modules/openapi-generator/src/main/resources/kotlin-client/libraries/multiplatform/api.mustache b/modules/openapi-generator/src/main/resources/kotlin-client/libraries/multiplatform/api.mustache
index fcf99cb542d..157fb37601d 100644
--- a/modules/openapi-generator/src/main/resources/kotlin-client/libraries/multiplatform/api.mustache
+++ b/modules/openapi-generator/src/main/resources/kotlin-client/libraries/multiplatform/api.mustache
@@ -76,11 +76,11 @@ import kotlinx.serialization.encoding.*
                 {{#formParams}}
                 {{#isArray}}
                 {{{paramName}}}?.onEach {
-                    append("{{{baseName}}}[]", it)
+                    {{#isFile}}append(it){{/isFile}}{{^isFile}}append("{{{baseName}}}", it){{/isFile}}
                 }
                 {{/isArray}}
                 {{^isArray}}
-                {{{paramName}}}?.apply { append("{{{baseName}}}", {{^isEnumOrRef}}{{{paramName}}}{{/isEnumOrRef}}{{#isEnumOrRef}}{{{paramName}}}.value{{/isEnumOrRef}}) }
+                {{{paramName}}}?.apply { {{#isFile}}append({{{baseName}}}){{/isFile}}{{^isFile}}append("{{{baseName}}}", {{^isEnumOrRef}}{{{paramName}}}{{/isEnumOrRef}}{{#isEnumOrRef}}{{{paramName}}}.value{{/isEnumOrRef}}){{/isFile}} }
                 {{/isArray}}
                 {{/formParams}}
             }
diff --git a/samples/client/petstore/kotlin-default-values-multiplatform/src/commonMain/kotlin/org/openapitools/client/apis/DefaultApi.kt b/samples/client/petstore/kotlin-default-values-multiplatform/src/commonMain/kotlin/org/openapitools/client/apis/DefaultApi.kt
index 3e5ce541214..d27ffacb3d9 100644
--- a/samples/client/petstore/kotlin-default-values-multiplatform/src/commonMain/kotlin/org/openapitools/client/apis/DefaultApi.kt
+++ b/samples/client/petstore/kotlin-default-values-multiplatform/src/commonMain/kotlin/org/openapitools/client/apis/DefaultApi.kt
@@ -90,7 +90,7 @@ open class DefaultApi : ApiClient {
                 fn2?.apply { append("fn2", fn2) }
                 fn3?.apply { append("fn3", fn3) }
                 fn4?.onEach {
-                    append("fn4[]", it)
+                    append("fn4", it)
                 }
             }
 
diff --git a/samples/client/petstore/kotlin-jvm-ktor-gson/docs/PetApi.md b/samples/client/petstore/kotlin-jvm-ktor-gson/docs/PetApi.md
index 94d0a303a87..0b928e328e6 100644
--- a/samples/client/petstore/kotlin-jvm-ktor-gson/docs/PetApi.md
+++ b/samples/client/petstore/kotlin-jvm-ktor-gson/docs/PetApi.md
@@ -360,7 +360,7 @@ uploads an image
 val apiInstance = PetApi()
 val petId : kotlin.Long = 789 // kotlin.Long | ID of pet to update
 val additionalMetadata : kotlin.String = additionalMetadata_example // kotlin.String | Additional data to pass to server
-val file : io.ktor.client.request.forms.InputProvider = BINARY_DATA_HERE // io.ktor.client.request.forms.InputProvider | file to upload
+val file : io.ktor.client.request.forms.FormPart<io.ktor.client.request.forms.InputProvider> = BINARY_DATA_HERE // io.ktor.client.request.forms.FormPart<io.ktor.client.request.forms.InputProvider> | file to upload
 try {
     val result : ModelApiResponse = apiInstance.uploadFile(petId, additionalMetadata, file)
     println(result)
@@ -378,7 +378,7 @@ try {
 | **additionalMetadata** | **kotlin.String**| Additional data to pass to server | [optional] |
 | Name | Type | Description  | Notes |
 | ------------- | ------------- | ------------- | ------------- |
-| **file** | **io.ktor.client.request.forms.InputProvider**| file to upload | [optional] |
+| **file** | **io.ktor.client.request.forms.FormPart&lt;io.ktor.client.request.forms.InputProvider&gt;**| file to upload | [optional] |
 
 ### Return type
 
diff --git a/samples/client/petstore/kotlin-jvm-ktor-gson/src/main/kotlin/org/openapitools/client/apis/PetApi.kt b/samples/client/petstore/kotlin-jvm-ktor-gson/src/main/kotlin/org/openapitools/client/apis/PetApi.kt
index 81e360424d3..b26f64edb46 100644
--- a/samples/client/petstore/kotlin-jvm-ktor-gson/src/main/kotlin/org/openapitools/client/apis/PetApi.kt
+++ b/samples/client/petstore/kotlin-jvm-ktor-gson/src/main/kotlin/org/openapitools/client/apis/PetApi.kt
@@ -290,14 +290,14 @@ import java.text.DateFormat
          * @return ModelApiResponse
         */
             @Suppress("UNCHECKED_CAST")
-        open suspend fun uploadFile(petId: kotlin.Long, additionalMetadata: kotlin.String?, file: io.ktor.client.request.forms.InputProvider?): HttpResponse<ModelApiResponse> {
+        open suspend fun uploadFile(petId: kotlin.Long, additionalMetadata: kotlin.String?, file: io.ktor.client.request.forms.FormPart<io.ktor.client.request.forms.InputProvider>?): HttpResponse<ModelApiResponse> {
 
             val localVariableAuthNames = listOf<String>("petstore_auth")
 
             val localVariableBody = 
                         formData {
                         additionalMetadata?.apply { append("additionalMetadata", additionalMetadata) }
-                        file?.apply { append("file", file) }
+                        file?.apply { append(file) }
                         }
 
             val localVariableQuery = mutableMapOf<String, List<String>>()
diff --git a/samples/client/petstore/kotlin-jvm-ktor-jackson/docs/PetApi.md b/samples/client/petstore/kotlin-jvm-ktor-jackson/docs/PetApi.md
index 94d0a303a87..0b928e328e6 100644
--- a/samples/client/petstore/kotlin-jvm-ktor-jackson/docs/PetApi.md
+++ b/samples/client/petstore/kotlin-jvm-ktor-jackson/docs/PetApi.md
@@ -360,7 +360,7 @@ uploads an image
 val apiInstance = PetApi()
 val petId : kotlin.Long = 789 // kotlin.Long | ID of pet to update
 val additionalMetadata : kotlin.String = additionalMetadata_example // kotlin.String | Additional data to pass to server
-val file : io.ktor.client.request.forms.InputProvider = BINARY_DATA_HERE // io.ktor.client.request.forms.InputProvider | file to upload
+val file : io.ktor.client.request.forms.FormPart<io.ktor.client.request.forms.InputProvider> = BINARY_DATA_HERE // io.ktor.client.request.forms.FormPart<io.ktor.client.request.forms.InputProvider> | file to upload
 try {
     val result : ModelApiResponse = apiInstance.uploadFile(petId, additionalMetadata, file)
     println(result)
@@ -378,7 +378,7 @@ try {
 | **additionalMetadata** | **kotlin.String**| Additional data to pass to server | [optional] |
 | Name | Type | Description  | Notes |
 | ------------- | ------------- | ------------- | ------------- |
-| **file** | **io.ktor.client.request.forms.InputProvider**| file to upload | [optional] |
+| **file** | **io.ktor.client.request.forms.FormPart&lt;io.ktor.client.request.forms.InputProvider&gt;**| file to upload | [optional] |
 
 ### Return type
 
diff --git a/samples/client/petstore/kotlin-jvm-ktor-jackson/src/main/kotlin/org/openapitools/client/apis/PetApi.kt b/samples/client/petstore/kotlin-jvm-ktor-jackson/src/main/kotlin/org/openapitools/client/apis/PetApi.kt
index c83bd1405d5..d81dff91aa7 100644
--- a/samples/client/petstore/kotlin-jvm-ktor-jackson/src/main/kotlin/org/openapitools/client/apis/PetApi.kt
+++ b/samples/client/petstore/kotlin-jvm-ktor-jackson/src/main/kotlin/org/openapitools/client/apis/PetApi.kt
@@ -288,14 +288,14 @@ import com.fasterxml.jackson.databind.ObjectMapper
          * @return ModelApiResponse
         */
             @Suppress("UNCHECKED_CAST")
-        open suspend fun uploadFile(petId: kotlin.Long, additionalMetadata: kotlin.String?, file: io.ktor.client.request.forms.InputProvider?): HttpResponse<ModelApiResponse> {
+        open suspend fun uploadFile(petId: kotlin.Long, additionalMetadata: kotlin.String?, file: io.ktor.client.request.forms.FormPart<io.ktor.client.request.forms.InputProvider>?): HttpResponse<ModelApiResponse> {
 
             val localVariableAuthNames = listOf<String>("petstore_auth")
 
             val localVariableBody = 
                         formData {
                         additionalMetadata?.apply { append("additionalMetadata", additionalMetadata) }
-                        file?.apply { append("file", file) }
+                        file?.apply { append(file) }
                         }
 
             val localVariableQuery = mutableMapOf<String, List<String>>()
diff --git a/samples/client/petstore/kotlin-jvm-ktor-kotlinx_serialization/docs/PetApi.md b/samples/client/petstore/kotlin-jvm-ktor-kotlinx_serialization/docs/PetApi.md
index b6eff247cc2..0a13a8fa8ce 100644
--- a/samples/client/petstore/kotlin-jvm-ktor-kotlinx_serialization/docs/PetApi.md
+++ b/samples/client/petstore/kotlin-jvm-ktor-kotlinx_serialization/docs/PetApi.md
@@ -372,7 +372,7 @@ uploads an image
 val apiInstance = PetApi()
 val petId : kotlin.Long = 789 // kotlin.Long | ID of pet to update
 val additionalMetadata : kotlin.String = additionalMetadata_example // kotlin.String | Additional data to pass to server
-val file : io.ktor.client.request.forms.InputProvider = BINARY_DATA_HERE // io.ktor.client.request.forms.InputProvider | file to upload
+val file : io.ktor.client.request.forms.FormPart<io.ktor.client.request.forms.InputProvider> = BINARY_DATA_HERE // io.ktor.client.request.forms.FormPart<io.ktor.client.request.forms.InputProvider> | file to upload
 try {
     val result : ModelApiResponse = apiInstance.uploadFile(petId, additionalMetadata, file)
     println(result)
@@ -390,7 +390,7 @@ try {
 | **additionalMetadata** | **kotlin.String**| Additional data to pass to server | [optional] |
 | Name | Type | Description  | Notes |
 | ------------- | ------------- | ------------- | ------------- |
-| **file** | **io.ktor.client.request.forms.InputProvider**| file to upload | [optional] |
+| **file** | **io.ktor.client.request.forms.FormPart&lt;io.ktor.client.request.forms.InputProvider&gt;**| file to upload | [optional] |
 
 ### Return type
 
diff --git a/samples/client/petstore/kotlin-jvm-ktor-kotlinx_serialization/src/main/kotlin/org/openapitools/client/apis/PetApi.kt b/samples/client/petstore/kotlin-jvm-ktor-kotlinx_serialization/src/main/kotlin/org/openapitools/client/apis/PetApi.kt
index f1280d1bff4..9b1780135f2 100644
--- a/samples/client/petstore/kotlin-jvm-ktor-kotlinx_serialization/src/main/kotlin/org/openapitools/client/apis/PetApi.kt
+++ b/samples/client/petstore/kotlin-jvm-ktor-kotlinx_serialization/src/main/kotlin/org/openapitools/client/apis/PetApi.kt
@@ -287,14 +287,14 @@ import io.ktor.http.ParametersBuilder
          * @return ModelApiResponse
         */
             @Suppress("UNCHECKED_CAST")
-        open suspend fun uploadFile(petId: kotlin.Long, additionalMetadata: kotlin.String?, file: io.ktor.client.request.forms.InputProvider?): HttpResponse<ModelApiResponse> {
+        open suspend fun uploadFile(petId: kotlin.Long, additionalMetadata: kotlin.String?, file: io.ktor.client.request.forms.FormPart<io.ktor.client.request.forms.InputProvider>?): HttpResponse<ModelApiResponse> {
 
             val localVariableAuthNames = listOf<String>("petstore_auth")
 
             val localVariableBody = 
                         formData {
                         additionalMetadata?.apply { append("additionalMetadata", additionalMetadata) }
-                        file?.apply { append("file", file) }
+                        file?.apply { append(file) }
                         }
 
             val localVariableQuery = mutableMapOf<String, List<String>>()
diff --git a/samples/client/petstore/kotlin-multiplatform-kotlinx-datetime/docs/PetApi.md b/samples/client/petstore/kotlin-multiplatform-kotlinx-datetime/docs/PetApi.md
index 94d0a303a87..0b928e328e6 100644
--- a/samples/client/petstore/kotlin-multiplatform-kotlinx-datetime/docs/PetApi.md
+++ b/samples/client/petstore/kotlin-multiplatform-kotlinx-datetime/docs/PetApi.md
@@ -360,7 +360,7 @@ uploads an image
 val apiInstance = PetApi()
 val petId : kotlin.Long = 789 // kotlin.Long | ID of pet to update
 val additionalMetadata : kotlin.String = additionalMetadata_example // kotlin.String | Additional data to pass to server
-val file : io.ktor.client.request.forms.InputProvider = BINARY_DATA_HERE // io.ktor.client.request.forms.InputProvider | file to upload
+val file : io.ktor.client.request.forms.FormPart<io.ktor.client.request.forms.InputProvider> = BINARY_DATA_HERE // io.ktor.client.request.forms.FormPart<io.ktor.client.request.forms.InputProvider> | file to upload
 try {
     val result : ModelApiResponse = apiInstance.uploadFile(petId, additionalMetadata, file)
     println(result)
@@ -378,7 +378,7 @@ try {
 | **additionalMetadata** | **kotlin.String**| Additional data to pass to server | [optional] |
 | Name | Type | Description  | Notes |
 | ------------- | ------------- | ------------- | ------------- |
-| **file** | **io.ktor.client.request.forms.InputProvider**| file to upload | [optional] |
+| **file** | **io.ktor.client.request.forms.FormPart&lt;io.ktor.client.request.forms.InputProvider&gt;**| file to upload | [optional] |
 
 ### Return type
 
diff --git a/samples/client/petstore/kotlin-multiplatform-kotlinx-datetime/src/commonMain/kotlin/org/openapitools/client/apis/PetApi.kt b/samples/client/petstore/kotlin-multiplatform-kotlinx-datetime/src/commonMain/kotlin/org/openapitools/client/apis/PetApi.kt
index 692c2893f35..b13983df903 100644
--- a/samples/client/petstore/kotlin-multiplatform-kotlinx-datetime/src/commonMain/kotlin/org/openapitools/client/apis/PetApi.kt
+++ b/samples/client/petstore/kotlin-multiplatform-kotlinx-datetime/src/commonMain/kotlin/org/openapitools/client/apis/PetApi.kt
@@ -324,14 +324,14 @@ open class PetApi : ApiClient {
      * @return ModelApiResponse
      */
     @Suppress("UNCHECKED_CAST")
-    open suspend fun uploadFile(petId: kotlin.Long, additionalMetadata: kotlin.String? = null, file: io.ktor.client.request.forms.InputProvider? = null): HttpResponse<ModelApiResponse> {
+    open suspend fun uploadFile(petId: kotlin.Long, additionalMetadata: kotlin.String? = null, file: io.ktor.client.request.forms.FormPart<io.ktor.client.request.forms.InputProvider>? = null): HttpResponse<ModelApiResponse> {
 
         val localVariableAuthNames = listOf<String>("petstore_auth")
 
         val localVariableBody = 
             formData {
                 additionalMetadata?.apply { append("additionalMetadata", additionalMetadata) }
-                file?.apply { append("file", file) }
+                file?.apply { append(file) }
             }
 
         val localVariableQuery = mutableMapOf<String, List<String>>()
diff --git a/samples/client/petstore/kotlin-multiplatform/docs/PetApi.md b/samples/client/petstore/kotlin-multiplatform/docs/PetApi.md
index 94d0a303a87..0b928e328e6 100644
--- a/samples/client/petstore/kotlin-multiplatform/docs/PetApi.md
+++ b/samples/client/petstore/kotlin-multiplatform/docs/PetApi.md
@@ -360,7 +360,7 @@ uploads an image
 val apiInstance = PetApi()
 val petId : kotlin.Long = 789 // kotlin.Long | ID of pet to update
 val additionalMetadata : kotlin.String = additionalMetadata_example // kotlin.String | Additional data to pass to server
-val file : io.ktor.client.request.forms.InputProvider = BINARY_DATA_HERE // io.ktor.client.request.forms.InputProvider | file to upload
+val file : io.ktor.client.request.forms.FormPart<io.ktor.client.request.forms.InputProvider> = BINARY_DATA_HERE // io.ktor.client.request.forms.FormPart<io.ktor.client.request.forms.InputProvider> | file to upload
 try {
     val result : ModelApiResponse = apiInstance.uploadFile(petId, additionalMetadata, file)
     println(result)
@@ -378,7 +378,7 @@ try {
 | **additionalMetadata** | **kotlin.String**| Additional data to pass to server | [optional] |
 | Name | Type | Description  | Notes |
 | ------------- | ------------- | ------------- | ------------- |
-| **file** | **io.ktor.client.request.forms.InputProvider**| file to upload | [optional] |
+| **file** | **io.ktor.client.request.forms.FormPart&lt;io.ktor.client.request.forms.InputProvider&gt;**| file to upload | [optional] |
 
 ### Return type
 
diff --git a/samples/client/petstore/kotlin-multiplatform/src/commonMain/kotlin/org/openapitools/client/apis/PetApi.kt b/samples/client/petstore/kotlin-multiplatform/src/commonMain/kotlin/org/openapitools/client/apis/PetApi.kt
index 692c2893f35..b13983df903 100644
--- a/samples/client/petstore/kotlin-multiplatform/src/commonMain/kotlin/org/openapitools/client/apis/PetApi.kt
+++ b/samples/client/petstore/kotlin-multiplatform/src/commonMain/kotlin/org/openapitools/client/apis/PetApi.kt
@@ -324,14 +324,14 @@ open class PetApi : ApiClient {
      * @return ModelApiResponse
      */
     @Suppress("UNCHECKED_CAST")
-    open suspend fun uploadFile(petId: kotlin.Long, additionalMetadata: kotlin.String? = null, file: io.ktor.client.request.forms.InputProvider? = null): HttpResponse<ModelApiResponse> {
+    open suspend fun uploadFile(petId: kotlin.Long, additionalMetadata: kotlin.String? = null, file: io.ktor.client.request.forms.FormPart<io.ktor.client.request.forms.InputProvider>? = null): HttpResponse<ModelApiResponse> {
 
         val localVariableAuthNames = listOf<String>("petstore_auth")
 
         val localVariableBody = 
             formData {
                 additionalMetadata?.apply { append("additionalMetadata", additionalMetadata) }
-                file?.apply { append("file", file) }
+                file?.apply { append(file) }
             }
 
         val localVariableQuery = mutableMapOf<String, List<String>>()