diff --git a/modules/openapi-generator/src/main/resources/kotlin-client/libraries/jvm-spring-restclient/api.mustache b/modules/openapi-generator/src/main/resources/kotlin-client/libraries/jvm-spring-restclient/api.mustache
index dc90d004dbdc..1d2608baecbb 100644
--- a/modules/openapi-generator/src/main/resources/kotlin-client/libraries/jvm-spring-restclient/api.mustache
+++ b/modules/openapi-generator/src/main/resources/kotlin-client/libraries/jvm-spring-restclient/api.mustache
@@ -121,8 +121,8 @@ import {{packageName}}.infrastructure.*
         {{#headerParams}}
         {{{paramName}}}{{^required}}?{{/required}}.apply { localVariableHeaders["{{baseName}}"] = {{#isContainer}}this.joinToString(separator = collectionDelimiter("{{collectionFormat}}")){{/isContainer}}{{^isContainer}}this.toString(){{/isContainer}} }
         {{/headerParams}}
-        {{^hasFormParams}}{{#hasConsumes}}{{#consumes}}localVariableHeaders["Content-Type"] = "{{{mediaType}}}"
-        {{/consumes}}{{/hasConsumes}}{{/hasFormParams}}{{#hasProduces}}localVariableHeaders["Accept"] = "{{#produces}}{{{mediaType}}}{{^-last}}, {{/-last}}{{/produces}}"
+        {{^hasFormParams}}{{#hasConsumes}}{{#consumes.0}}localVariableHeaders["Content-Type"] = "{{{mediaType}}}"
+        {{/consumes.0}}{{/hasConsumes}}{{/hasFormParams}}{{#hasProduces}}localVariableHeaders["Accept"] = "{{#produces}}{{{mediaType}}}{{^-last}}, {{/-last}}{{/produces}}"
 {{/hasProduces}}
 
         val params = mutableMapOf<String, Any>(
diff --git a/samples/client/petstore/kotlin-jvm-spring-3-restclient/src/main/kotlin/org/openapitools/client/apis/PetApi.kt b/samples/client/petstore/kotlin-jvm-spring-3-restclient/src/main/kotlin/org/openapitools/client/apis/PetApi.kt
index 64512b2da6f2..4f8f8115a801 100644
--- a/samples/client/petstore/kotlin-jvm-spring-3-restclient/src/main/kotlin/org/openapitools/client/apis/PetApi.kt
+++ b/samples/client/petstore/kotlin-jvm-spring-3-restclient/src/main/kotlin/org/openapitools/client/apis/PetApi.kt
@@ -65,7 +65,6 @@ open class PetApi(client: RestClient) : ApiClient(client) {
         val localVariableQuery = mutableMapOf<kotlin.String, kotlin.collections.List<kotlin.String>>()
         val localVariableHeaders: MutableMap<String, String> = mutableMapOf()
         localVariableHeaders["Content-Type"] = "application/json"
-        localVariableHeaders["Content-Type"] = "application/xml"
         localVariableHeaders["Accept"] = "application/xml, application/json"
 
         val params = mutableMapOf<String, Any>(
@@ -261,7 +260,6 @@ open class PetApi(client: RestClient) : ApiClient(client) {
         val localVariableQuery = mutableMapOf<kotlin.String, kotlin.collections.List<kotlin.String>>()
         val localVariableHeaders: MutableMap<String, String> = mutableMapOf()
         localVariableHeaders["Content-Type"] = "application/json"
-        localVariableHeaders["Content-Type"] = "application/xml"
         localVariableHeaders["Accept"] = "application/xml, application/json"
 
         val params = mutableMapOf<String, Any>(