diff --git a/modules/openapi-generator/src/main/resources/go/client.mustache b/modules/openapi-generator/src/main/resources/go/client.mustache
index 49fbd071ff0..e66c6317c84 100644
--- a/modules/openapi-generator/src/main/resources/go/client.mustache
+++ b/modules/openapi-generator/src/main/resources/go/client.mustache
@@ -225,7 +225,11 @@ func parameterAddToQuery(queryParams interface{}, keyPrefix string, obj interfac
 
 	switch valuesMap := queryParams.(type) {
 		case url.Values:
-			valuesMap.Add( keyPrefix, value )
+			if collectionType == "csv" && valuesMap.Get(keyPrefix) != "" {
+				valuesMap.Set(keyPrefix, valuesMap.Get(keyPrefix) + "," + value)
+			} else {
+				valuesMap.Add(keyPrefix, value)
+			}
 			break
 		case map[string]string:
 			valuesMap[keyPrefix] = value
diff --git a/samples/client/petstore/go/go-petstore/client.go b/samples/client/petstore/go/go-petstore/client.go
index 02aeed0b0f4..8ec8dc77c78 100644
--- a/samples/client/petstore/go/go-petstore/client.go
+++ b/samples/client/petstore/go/go-petstore/client.go
@@ -231,7 +231,11 @@ func parameterAddToQuery(queryParams interface{}, keyPrefix string, obj interfac
 
 	switch valuesMap := queryParams.(type) {
 		case url.Values:
-			valuesMap.Add( keyPrefix, value )
+			if collectionType == "csv" && valuesMap.Get(keyPrefix) != "" {
+				valuesMap.Set(keyPrefix, valuesMap.Get(keyPrefix) + "," + value)
+			} else {
+				valuesMap.Add(keyPrefix, value)
+			}
 			break
 		case map[string]string:
 			valuesMap[keyPrefix] = value
diff --git a/samples/openapi3/client/extensions/x-auth-id-alias/go-experimental/client.go b/samples/openapi3/client/extensions/x-auth-id-alias/go-experimental/client.go
index 17aa6861b06..9cf02fe1f70 100644
--- a/samples/openapi3/client/extensions/x-auth-id-alias/go-experimental/client.go
+++ b/samples/openapi3/client/extensions/x-auth-id-alias/go-experimental/client.go
@@ -215,7 +215,11 @@ func parameterAddToQuery(queryParams interface{}, keyPrefix string, obj interfac
 
 	switch valuesMap := queryParams.(type) {
 		case url.Values:
-			valuesMap.Add( keyPrefix, value )
+			if collectionType == "csv" && valuesMap.Get(keyPrefix) != "" {
+				valuesMap.Set(keyPrefix, valuesMap.Get(keyPrefix) + "," + value)
+			} else {
+				valuesMap.Add(keyPrefix, value)
+			}
 			break
 		case map[string]string:
 			valuesMap[keyPrefix] = value
diff --git a/samples/openapi3/client/petstore/go/go-petstore/client.go b/samples/openapi3/client/petstore/go/go-petstore/client.go
index 8db7aa62f1c..7f9f73dba8b 100644
--- a/samples/openapi3/client/petstore/go/go-petstore/client.go
+++ b/samples/openapi3/client/petstore/go/go-petstore/client.go
@@ -234,7 +234,11 @@ func parameterAddToQuery(queryParams interface{}, keyPrefix string, obj interfac
 
 	switch valuesMap := queryParams.(type) {
 		case url.Values:
-			valuesMap.Add( keyPrefix, value )
+			if collectionType == "csv" && valuesMap.Get(keyPrefix) != "" {
+				valuesMap.Set(keyPrefix, valuesMap.Get(keyPrefix) + "," + value)
+			} else {
+				valuesMap.Add(keyPrefix, value)
+			}
 			break
 		case map[string]string:
 			valuesMap[keyPrefix] = value