diff --git a/modules/openapi-generator/src/main/resources/ruby-client/api.mustache b/modules/openapi-generator/src/main/resources/ruby-client/api.mustache
index 6bfa987b65ea..97f38c704126 100644
--- a/modules/openapi-generator/src/main/resources/ruby-client/api.mustache
+++ b/modules/openapi-generator/src/main/resources/ruby-client/api.mustache
@@ -176,12 +176,22 @@ module {{moduleName}}
       query_params = opts[:query_params] || {}
       {{#queryParams}}
       {{#required}}
+      {{#queryIsJsonMimeType}}
+      query_params[:'{{{baseName}}}'] = {{{paramName}}}.to_json
+      {{/queryIsJsonMimeType}}
+      {{^queryIsJsonMimeType}}
       query_params[:'{{{baseName}}}'] = {{#collectionFormat}}@api_client.build_collection_param({{{paramName}}}, :{{{collectionFormat}}}){{/collectionFormat}}{{^collectionFormat}}{{{paramName}}}{{/collectionFormat}}
+      {{/queryIsJsonMimeType}}
       {{/required}}
       {{/queryParams}}
       {{#queryParams}}
       {{^required}}
+      {{#queryIsJsonMimeType}}
+      query_params[:'{{{baseName}}}'] = opts[:'{{{paramName}}}'].to_json if !opts[:'{{{paramName}}}'].nil?
+      {{/queryIsJsonMimeType}}
+      {{^queryIsJsonMimeType}}
       query_params[:'{{{baseName}}}'] = {{#collectionFormat}}@api_client.build_collection_param(opts[:'{{{paramName}}}'], :{{{collectionFormat}}}){{/collectionFormat}}{{^collectionFormat}}opts[:'{{{paramName}}}']{{/collectionFormat}} if !opts[:'{{{paramName}}}'].nil?
+      {{/queryIsJsonMimeType}}
       {{/required}}
       {{/queryParams}}
 
diff --git a/modules/openapi-generator/src/test/java/org/openapitools/codegen/ruby/RubyClientCodegenTest.java b/modules/openapi-generator/src/test/java/org/openapitools/codegen/ruby/RubyClientCodegenTest.java
index 4e554969228a..ed256377bc80 100644
--- a/modules/openapi-generator/src/test/java/org/openapitools/codegen/ruby/RubyClientCodegenTest.java
+++ b/modules/openapi-generator/src/test/java/org/openapitools/codegen/ruby/RubyClientCodegenTest.java
@@ -749,4 +749,17 @@ public void testRegularExpressionOpenAPISchemaVersion3() {
         // patten_starts_ends_with_slash '/root/'
         Assert.assertEquals(op.allParams.get(8).pattern, "/root/");
     }
+
+    @Test
+    public void testQueryParamJsonSerializationSetsQueryIsJsonMimeType() {
+        RubyClientCodegen codegen = new RubyClientCodegen();
+        final OpenAPI openAPI = TestUtils.parseFlattenSpec("src/test/resources/3_0/echo_api.yaml");
+        codegen.setOpenAPI(openAPI);
+        String path = "/query/style_jsonSerialization/object";
+        CodegenOperation op = codegen.fromOperation(path, "GET", openAPI.getPaths().get(path).getGet(), null);
+
+        Assert.assertEquals(op.queryParams.size(), 2);
+        assertTrue(op.queryParams.stream().allMatch(p -> p.queryIsJsonMimeType),
+                "All content:application/json query params should have queryIsJsonMimeType=true");
+    }
 }
diff --git a/samples/client/echo_api/ruby-faraday/lib/openapi_client/api/query_api.rb b/samples/client/echo_api/ruby-faraday/lib/openapi_client/api/query_api.rb
index 37e2b1501988..84273de2741a 100644
--- a/samples/client/echo_api/ruby-faraday/lib/openapi_client/api/query_api.rb
+++ b/samples/client/echo_api/ruby-faraday/lib/openapi_client/api/query_api.rb
@@ -664,8 +664,8 @@ def test_query_style_json_serialization_object_with_http_info(opts = {})
 
       # query parameters
       query_params = opts[:query_params] || {}
-      query_params[:'json_serialized_object_ref_string_query'] = opts[:'json_serialized_object_ref_string_query'] if !opts[:'json_serialized_object_ref_string_query'].nil?
-      query_params[:'json_serialized_object_array_ref_string_query'] = @api_client.build_collection_param(opts[:'json_serialized_object_array_ref_string_query'], :csv) if !opts[:'json_serialized_object_array_ref_string_query'].nil?
+      query_params[:'json_serialized_object_ref_string_query'] = opts[:'json_serialized_object_ref_string_query'].to_json if !opts[:'json_serialized_object_ref_string_query'].nil?
+      query_params[:'json_serialized_object_array_ref_string_query'] = opts[:'json_serialized_object_array_ref_string_query'].to_json if !opts[:'json_serialized_object_array_ref_string_query'].nil?
 
       # header parameters
       header_params = opts[:header_params] || {}
diff --git a/samples/client/echo_api/ruby-httpx/lib/openapi_client/api/query_api.rb b/samples/client/echo_api/ruby-httpx/lib/openapi_client/api/query_api.rb
index 37e2b1501988..84273de2741a 100644
--- a/samples/client/echo_api/ruby-httpx/lib/openapi_client/api/query_api.rb
+++ b/samples/client/echo_api/ruby-httpx/lib/openapi_client/api/query_api.rb
@@ -664,8 +664,8 @@ def test_query_style_json_serialization_object_with_http_info(opts = {})
 
       # query parameters
       query_params = opts[:query_params] || {}
-      query_params[:'json_serialized_object_ref_string_query'] = opts[:'json_serialized_object_ref_string_query'] if !opts[:'json_serialized_object_ref_string_query'].nil?
-      query_params[:'json_serialized_object_array_ref_string_query'] = @api_client.build_collection_param(opts[:'json_serialized_object_array_ref_string_query'], :csv) if !opts[:'json_serialized_object_array_ref_string_query'].nil?
+      query_params[:'json_serialized_object_ref_string_query'] = opts[:'json_serialized_object_ref_string_query'].to_json if !opts[:'json_serialized_object_ref_string_query'].nil?
+      query_params[:'json_serialized_object_array_ref_string_query'] = opts[:'json_serialized_object_array_ref_string_query'].to_json if !opts[:'json_serialized_object_array_ref_string_query'].nil?
 
       # header parameters
       header_params = opts[:header_params] || {}
diff --git a/samples/client/echo_api/ruby-typhoeus/lib/openapi_client/api/query_api.rb b/samples/client/echo_api/ruby-typhoeus/lib/openapi_client/api/query_api.rb
index 37e2b1501988..84273de2741a 100644
--- a/samples/client/echo_api/ruby-typhoeus/lib/openapi_client/api/query_api.rb
+++ b/samples/client/echo_api/ruby-typhoeus/lib/openapi_client/api/query_api.rb
@@ -664,8 +664,8 @@ def test_query_style_json_serialization_object_with_http_info(opts = {})
 
       # query parameters
       query_params = opts[:query_params] || {}
-      query_params[:'json_serialized_object_ref_string_query'] = opts[:'json_serialized_object_ref_string_query'] if !opts[:'json_serialized_object_ref_string_query'].nil?
-      query_params[:'json_serialized_object_array_ref_string_query'] = @api_client.build_collection_param(opts[:'json_serialized_object_array_ref_string_query'], :csv) if !opts[:'json_serialized_object_array_ref_string_query'].nil?
+      query_params[:'json_serialized_object_ref_string_query'] = opts[:'json_serialized_object_ref_string_query'].to_json if !opts[:'json_serialized_object_ref_string_query'].nil?
+      query_params[:'json_serialized_object_array_ref_string_query'] = opts[:'json_serialized_object_array_ref_string_query'].to_json if !opts[:'json_serialized_object_array_ref_string_query'].nil?
 
       # header parameters
       header_params = opts[:header_params] || {}