diff --git a/packages/strapi-plugin-content-manager/admin/src/components/InputUID/Options/index.js b/packages/strapi-plugin-content-manager/admin/src/components/InputUID/Options/index.js
index 338004641e..ef1ac73955 100644
--- a/packages/strapi-plugin-content-manager/admin/src/components/InputUID/Options/index.js
+++ b/packages/strapi-plugin-content-manager/admin/src/components/InputUID/Options/index.js
@@ -2,7 +2,7 @@ import React from 'react';
 import PropTypes from 'prop-types';
 import { FormattedMessage } from 'react-intl';
 
-import getTrad from '../../../utils/getTrad'
+import getTrad from '../../../utils/getTrad';
 import OptionsWrapper from './wrapper';
 import Option from './Option';
 import OptionsTitle from './OptionsTitle';
diff --git a/packages/strapi-plugin-content-type-builder/admin/src/containers/FormModal/utils/forms.js b/packages/strapi-plugin-content-type-builder/admin/src/containers/FormModal/utils/forms.js
index aa8054e5f7..fc07065583 100644
--- a/packages/strapi-plugin-content-type-builder/admin/src/containers/FormModal/utils/forms.js
+++ b/packages/strapi-plugin-content-type-builder/admin/src/containers/FormModal/utils/forms.js
@@ -215,6 +215,15 @@ const forms = {
               .array()
               .of(yup.string())
               .min(1, errorsTrads.min)
+              .test({
+                name: 'areEnumValuesUnique',
+                message: getTrad('error.validation.enum-duplicate'),
+                test: values => {
+                  const filtered = [...new Set(values)];
+
+                  return filtered.length === values.length;
+                },
+              })
               .matchesEnumRegex(errorsTrads.regex)
               .hasNotEmptyValues('Empty strings are not allowed', dataToValidate.enum),
             enumName: yup.string().nullable(),
diff --git a/packages/strapi-plugin-content-type-builder/admin/src/translations/en.json b/packages/strapi-plugin-content-type-builder/admin/src/translations/en.json
index 0da3f498a7..342d50514b 100644
--- a/packages/strapi-plugin-content-type-builder/admin/src/translations/en.json
+++ b/packages/strapi-plugin-content-type-builder/admin/src/translations/en.json
@@ -48,6 +48,7 @@
   "contentType.kind.change.warning": "You just changed the kind of a content type: API will be reset (routes, controllers, and services will be overwritten).",
   "contentType.UID.description": "The UID is used to generate the API routes and databases tables/collections",
   "error.contentTypeName.reserved-name": "This name cannot be used in your project as it might break other functionalities",
+  "error.validation.enum-duplicate": "Duplicate values are not allowed",
   "error.validation.minSupMax": "Can't be superior",
   "error.validation.relation.targetAttribute-taken": "This name exists in the target",
   "form.attribute.component.option.add": "Add a component",
diff --git a/packages/strapi-plugin-content-type-builder/controllers/validation/common.js b/packages/strapi-plugin-content-type-builder/controllers/validation/common.js
index 7c235370a5..797a013603 100644
--- a/packages/strapi-plugin-content-type-builder/controllers/validation/common.js
+++ b/packages/strapi-plugin-content-type-builder/controllers/validation/common.js
@@ -64,9 +64,19 @@ const isValidEnum = {
   test: val => val === '' || ENUM_REGEX.test(val),
 };
 
+const areEnumValuesUnique = {
+  name: 'areEnumValuesUnique',
+  message: '${path} cannot contain duplicate values',
+  test: values => {
+    const filtered = [...new Set(values)];
+
+    return filtered.length === values.length;
+  },
+};
+
 module.exports = {
   validators,
-
+  areEnumValuesUnique,
   isValidCollectionName,
   isValidCategoryName,
   isValidName,
diff --git a/packages/strapi-plugin-content-type-builder/controllers/validation/types.js b/packages/strapi-plugin-content-type-builder/controllers/validation/types.js
index 6269d32f00..b895796305 100644
--- a/packages/strapi-plugin-content-type-builder/controllers/validation/types.js
+++ b/packages/strapi-plugin-content-type-builder/controllers/validation/types.js
@@ -5,6 +5,7 @@ const yup = require('yup');
 
 const {
   validators,
+  areEnumValuesUnique,
   isValidName,
   isValidEnum,
   isValidUID,
@@ -17,11 +18,7 @@ const maxLengthIsGreaterThanOrEqualToMinLength = {
   message: 'maxLength must be greater or equal to minLength',
   test: function(value) {
     const { minLength } = this.parent;
-    if (
-      !_.isUndefined(minLength) &&
-      !_.isUndefined(value) &&
-      value < minLength
-    ) {
+    if (!_.isUndefined(minLength) && !_.isUndefined(value) && value < minLength) {
       return false;
     }
 
@@ -82,9 +79,7 @@ const getTypeShape = (attribute, { modelType, attributes } = {}) => {
           )
           .test(isValidUID),
         minLength: validators.minLength,
-        maxLength: validators.maxLength
-          .max(256)
-          .test(maxLengthIsGreaterThanOrEqualToMinLength),
+        maxLength: validators.maxLength.max(256).test(maxLengthIsGreaterThanOrEqualToMinLength),
       };
     }
 
@@ -126,10 +121,9 @@ const getTypeShape = (attribute, { modelType, attributes } = {}) => {
               .required()
           )
           .min(1)
+          .test(areEnumValuesUnique)
           .required(),
-        default: yup
-          .string()
-          .when('enum', enumVal => yup.string().oneOf(enumVal)),
+        default: yup.string().when('enum', enumVal => yup.string().oneOf(enumVal)),
         enumName: yup.string().test(isValidName),
         required: validators.required,
         unique: validators.unique,
@@ -225,10 +219,7 @@ const getTypeShape = (attribute, { modelType, attributes } = {}) => {
               const targetCompo = strapi.components[compoUID];
               if (!targetCompo) return true; // ignore this error as it will fail beforehand
 
-              if (
-                modelType === modelTypes.COMPONENT &&
-                hasComponent(targetCompo)
-              ) {
+              if (modelType === modelTypes.COMPONENT && hasComponent(targetCompo)) {
                 return this.createError({
                   path: this.path,
                   message: `${targetCompo.modelName} already as a nested compoent. You cannot have more than one level of nesting inside your components.`,
@@ -249,9 +240,7 @@ const getTypeShape = (attribute, { modelType, attributes } = {}) => {
         components: yup
           .array()
           .of(yup.string().required())
-          .test('isArray', '${path} must be an array', value =>
-            Array.isArray(value)
-          ),
+          .test('isArray', '${path} must be an array', value => Array.isArray(value)),
         min: yup.number(),
         max: yup.number(),
       };