diff --git a/modules/swagger-codegen/src/main/resources/ruby/api.mustache b/modules/swagger-codegen/src/main/resources/ruby/api.mustache
index 7071e72e849..8366246f467 100644
--- a/modules/swagger-codegen/src/main/resources/ruby/api.mustache
+++ b/modules/swagger-codegen/src/main/resources/ruby/api.mustache
@@ -50,9 +50,16 @@ module {{moduleName}}
       {{/required}}
       {{^required}}
       {{#isEnum}}
+      {{#collectionFormat}}
+      if opts[:'{{{paramName}}}'] && !opts[:'{{{paramName}}}'].all?{|item| [{{#allowableValues}}{{#values}}'{{{this}}}'{{^-last}}, {{/-last}}{{/values}}{{/allowableValues}}].include?(item)}
+        fail ArgumentError, 'invalid value for "{{{paramName}}}", must include one of {{#allowableValues}}{{#values}}{{{this}}}{{^-last}}, {{/-last}}{{/values}}{{/allowableValues}}'
+      end
+      {{/collectionFormat}}
+      {{^collectionFormat}}
       if opts[:'{{{paramName}}}'] && ![{{#allowableValues}}{{#values}}'{{{this}}}'{{^-last}}, {{/-last}}{{/values}}{{/allowableValues}}].include?(opts[:'{{{paramName}}}'])
         fail ArgumentError, 'invalid value for "{{{paramName}}}", must be one of {{#allowableValues}}{{#values}}{{{this}}}{{^-last}}, {{/-last}}{{/values}}{{/allowableValues}}'
       end
+      {{/collectionFormat}}
       {{/isEnum}}
       {{/required}}
       {{#hasValidation}}
diff --git a/samples/client/petstore/ruby/lib/petstore/api/fake_api.rb b/samples/client/petstore/ruby/lib/petstore/api/fake_api.rb
index 0eaba370798..3500dfbb52f 100644
--- a/samples/client/petstore/ruby/lib/petstore/api/fake_api.rb
+++ b/samples/client/petstore/ruby/lib/petstore/api/fake_api.rb
@@ -275,20 +275,20 @@ module Petstore
       if @api_client.config.debugging
         @api_client.config.logger.debug "Calling API: FakeApi.test_enum_parameters ..."
       end
-      if opts[:'enum_form_string_array'] && !['>', '$'].include?(opts[:'enum_form_string_array'])
-        fail ArgumentError, 'invalid value for "enum_form_string_array", must be one of >, $'
+      if opts[:'enum_form_string_array'] && !opts[:'enum_form_string_array'].all?{|item| ['>', '$'].include?(item)}
+        fail ArgumentError, 'invalid value for "enum_form_string_array", must include one of >, $'
       end
       if opts[:'enum_form_string'] && !['_abc', '-efg', '(xyz)'].include?(opts[:'enum_form_string'])
         fail ArgumentError, 'invalid value for "enum_form_string", must be one of _abc, -efg, (xyz)'
       end
-      if opts[:'enum_header_string_array'] && !['>', '$'].include?(opts[:'enum_header_string_array'])
-        fail ArgumentError, 'invalid value for "enum_header_string_array", must be one of >, $'
+      if opts[:'enum_header_string_array'] && !opts[:'enum_header_string_array'].all?{|item| ['>', '$'].include?(item)}
+        fail ArgumentError, 'invalid value for "enum_header_string_array", must include one of >, $'
       end
       if opts[:'enum_header_string'] && !['_abc', '-efg', '(xyz)'].include?(opts[:'enum_header_string'])
         fail ArgumentError, 'invalid value for "enum_header_string", must be one of _abc, -efg, (xyz)'
       end
-      if opts[:'enum_query_string_array'] && !['>', '$'].include?(opts[:'enum_query_string_array'])
-        fail ArgumentError, 'invalid value for "enum_query_string_array", must be one of >, $'
+      if opts[:'enum_query_string_array'] && !opts[:'enum_query_string_array'].all?{|item| ['>', '$'].include?(item)}
+        fail ArgumentError, 'invalid value for "enum_query_string_array", must include one of >, $'
       end
       if opts[:'enum_query_string'] && !['_abc', '-efg', '(xyz)'].include?(opts[:'enum_query_string'])
         fail ArgumentError, 'invalid value for "enum_query_string", must be one of _abc, -efg, (xyz)'