diff --git a/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/ElixirClientCodegen.java b/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/ElixirClientCodegen.java
index 99be37036d7..7928a50f3ea 100644
--- a/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/ElixirClientCodegen.java
+++ b/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/ElixirClientCodegen.java
@@ -570,7 +570,11 @@ public class ElixirClientCodegen extends DefaultCodegen {
      */
     @Override
     public String getTypeDeclaration(Schema p) {
-        if (ModelUtils.isArraySchema(p)) {
+        if (ModelUtils.isAnyType(p)) {
+            return "any()";
+        } else if(ModelUtils.isFreeFormObject(p, null)) {
+            return "%{optional(String.t) => any()}";
+        } else if (ModelUtils.isArraySchema(p)) {
             Schema inner = ModelUtils.getSchemaItems(p);
             return "[" + getTypeDeclaration(inner) + "]";
         } else if (ModelUtils.isMapSchema(p)) {
@@ -856,6 +860,10 @@ public class ElixirClientCodegen extends DefaultCodegen {
         private void buildTypespec(CodegenParameter param, StringBuilder sb) {
             if (param.dataType == null) {
                 sb.append("nil");
+            } else if (param.isAnyType) {
+                sb.append("any()");
+            } else if(param.isFreeFormObject) {
+                sb.append("%{optional(String.t) => any()}");
             } else if (param.isArray) {
                 // list(<subtype>)
                 sb.append("list(");
@@ -875,6 +883,10 @@ public class ElixirClientCodegen extends DefaultCodegen {
             if (property == null) {
                 LOGGER.error(
                         "CodegenProperty cannot be null. Please report the issue to https://github.com/openapitools/openapi-generator with the spec");
+            } else if (property.isAnyType) {
+                sb.append("any()");
+            } else if(property.isFreeFormObject) {
+                sb.append("%{optional(String.t) => any()}");
             } else if (property.isArray) {
                 sb.append("list(");
                 buildTypespec(property.items, sb);
diff --git a/modules/openapi-generator/src/test/resources/3_0/elixir/petstore-with-fake-endpoints-models-for-testing.yaml b/modules/openapi-generator/src/test/resources/3_0/elixir/petstore-with-fake-endpoints-models-for-testing.yaml
index 229450a390d..4c1654d2a2b 100644
--- a/modules/openapi-generator/src/test/resources/3_0/elixir/petstore-with-fake-endpoints-models-for-testing.yaml
+++ b/modules/openapi-generator/src/test/resources/3_0/elixir/petstore-with-fake-endpoints-models-for-testing.yaml
@@ -1012,6 +1012,40 @@ paths:
               $ref: "#/components/schemas/FreeFormObject"
         description: request body
         required: true
+  /fake/implicitFreeFormObject:
+    post:
+      tags:
+        - fake
+      summary: test free form object with implicit additionalProperties
+      description: ""
+      operationId: testImplicitFreeFormObject
+      responses:
+        "200":
+          description: successful operation
+      requestBody:
+        content:
+          application/json:
+            schema:
+              $ref: "#/components/schemas/ImplicitFreeFormObject"
+        description: request body
+        required: true
+  /fake/anyTypeObject:
+    post:
+      tags:
+        - fake
+      summary: test any type object
+      description: ""
+      operationId: testAnyTypeObject
+      responses:
+        "200":
+          description: successful operation
+      requestBody:
+        content:
+          application/json:
+            schema:
+              $ref: "#/components/schemas/AnyTypeObject"
+        description: request body
+        required: true
   /fake/stringMap-reference:
     post:
       tags:
@@ -1859,6 +1893,19 @@ components:
       type: object
       description: A schema consisting only of additional properties
       additionalProperties: true
+    ImplicitFreeFormObject:
+      type: object
+      description: A schema consisting only of additional properties (implicit)
+    AnyTypeObject:
+      oneOf:
+        - type: string
+        - type: number
+        - type: integer
+        - type: boolean
+        - type: object
+        - type: array
+          items: {}
+      nullable: true
     MapOfString:
       type: object
       description: A schema consisting only of additional properties of type string
diff --git a/samples/client/petstore/elixir/lib/openapi_petstore/api/fake.ex b/samples/client/petstore/elixir/lib/openapi_petstore/api/fake.ex
index 59ca8b472da..7067b04b079 100644
--- a/samples/client/petstore/elixir/lib/openapi_petstore/api/fake.ex
+++ b/samples/client/petstore/elixir/lib/openapi_petstore/api/fake.ex
@@ -304,6 +304,37 @@ defmodule OpenapiPetstore.Api.Fake do
     ])
   end
 
+  @doc """
+  test any type object
+  
+
+  ### Parameters
+
+  - `connection` (OpenapiPetstore.Connection): Connection to server
+  - `body` (any()): request body
+  - `opts` (keyword): Optional parameters
+
+  ### Returns
+
+  - `{:ok, nil}` on success
+  - `{:error, Tesla.Env.t}` on failure
+  """
+  @spec test_any_type_object(Tesla.Env.client, any(), keyword()) :: {:ok, nil} | {:error, Tesla.Env.t}
+  def test_any_type_object(connection, body, _opts \\ []) do
+    request =
+      %{}
+      |> method(:post)
+      |> url("/fake/anyTypeObject")
+      |> add_param(:body, :body, body)
+      |> Enum.into([])
+
+    connection
+    |> Connection.request(request)
+    |> evaluate_response([
+      {200, false}
+    ])
+  end
+
   @doc """
   For this test, the body has to be a binary file.
 
@@ -585,6 +616,37 @@ defmodule OpenapiPetstore.Api.Fake do
     ])
   end
 
+  @doc """
+  test free form object with implicit additionalProperties
+  
+
+  ### Parameters
+
+  - `connection` (OpenapiPetstore.Connection): Connection to server
+  - `body` (%{optional(String.t) => any()}): request body
+  - `opts` (keyword): Optional parameters
+
+  ### Returns
+
+  - `{:ok, nil}` on success
+  - `{:error, Tesla.Env.t}` on failure
+  """
+  @spec test_implicit_free_form_object(Tesla.Env.client, %{optional(String.t) => any()}, keyword()) :: {:ok, nil} | {:error, Tesla.Env.t}
+  def test_implicit_free_form_object(connection, body, _opts \\ []) do
+    request =
+      %{}
+      |> method(:post)
+      |> url("/fake/implicitFreeFormObject")
+      |> add_param(:body, :body, body)
+      |> Enum.into([])
+
+    connection
+    |> Connection.request(request)
+    |> evaluate_response([
+      {200, false}
+    ])
+  end
+
   @doc """
   test inline additionalProperties
   
diff --git a/samples/client/petstore/elixir/lib/openapi_petstore/model/nullable_class.ex b/samples/client/petstore/elixir/lib/openapi_petstore/model/nullable_class.ex
index 8fab347fad9..28891b8013d 100644
--- a/samples/client/petstore/elixir/lib/openapi_petstore/model/nullable_class.ex
+++ b/samples/client/petstore/elixir/lib/openapi_petstore/model/nullable_class.ex
@@ -29,12 +29,12 @@ defmodule OpenapiPetstore.Model.NullableClass do
     :string_prop => String.t | nil,
     :date_prop => Date.t | nil,
     :datetime_prop => DateTime.t | nil,
-    :array_nullable_prop => [map()] | nil,
-    :array_and_items_nullable_prop => [map()] | nil,
-    :array_items_nullable => [map()] | nil,
-    :object_nullable_prop => %{optional(String.t) => map()} | nil,
-    :object_and_items_nullable_prop => %{optional(String.t) => map()} | nil,
-    :object_items_nullable => %{optional(String.t) => map()} | nil
+    :array_nullable_prop => [%{optional(String.t) => any()}] | nil,
+    :array_and_items_nullable_prop => [%{optional(String.t) => any()}] | nil,
+    :array_items_nullable => [%{optional(String.t) => any()}] | nil,
+    :object_nullable_prop => %{optional(String.t) => any()} | nil,
+    :object_and_items_nullable_prop => %{optional(String.t) => any()} | nil,
+    :object_items_nullable => %{optional(String.t) => any()} | nil
   }
 
   alias OpenapiPetstore.Deserializer