diff --git a/Magento2/Sniffs/GraphQL/AbstractGraphQLSniff.php b/Magento2/Sniffs/GraphQL/AbstractGraphQLSniff.php
index b03cffe8..b9e95fae 100644
--- a/Magento2/Sniffs/GraphQL/AbstractGraphQLSniff.php
+++ b/Magento2/Sniffs/GraphQL/AbstractGraphQLSniff.php
@@ -10,6 +10,7 @@
  *
  * To obtain a valid license for using this software please contact us at license@techdivision.com
  */
+
 namespace Magento2\Sniffs\GraphQL;
 
 use PHP_CodeSniffer\Sniffs\Sniff;
@@ -38,13 +39,38 @@ protected function isCamelCase($name)
     }
 
     /**
-     * Returns whether <var>$name</var> is strictly lower case, potentially separated by underscores.
+     * Returns whether <var>$name</var> is specified in snake case (either all lower case or all upper case).
      *
      * @param string $name
+     * @param bool $upperCase If set to <kbd>true</kbd> checks for all upper case, otherwise all lower case
      * @return bool
      */
-    protected function isSnakeCase($name)
+    protected function isSnakeCase($name, $upperCase = false)
     {
-        return preg_match('/^[a-z][a-z0-9_]*$/', $name);
+        $pattern = $upperCase ? '/^[A-Z][A-Z0-9_]*$/' : '/^[a-z][a-z0-9_]*$/';
+        return preg_match($pattern, $name);
+    }
+
+    /**
+     * Searches for the first token that has <var>$tokenCode</var> in <var>$tokens</var> from position
+     * <var>$startPointer</var> (excluded).
+     *
+     * @param mixed $tokenCode
+     * @param array $tokens
+     * @param int $startPointer
+     * @return bool|int If token was found, returns its pointer, <kbd>false</kbd> otherwise
+     */
+    protected function seekToken($tokenCode, array $tokens, $startPointer = 0)
+    {
+        $numTokens = count($tokens);
+
+        for ($i = $startPointer + 1; $i < $numTokens; ++$i) {
+            if ($tokens[$i]['code'] === $tokenCode) {
+                return $i;
+            }
+        }
+
+        //if we came here we could not find the requested token
+        return false;
     }
 }
diff --git a/Magento2/Sniffs/GraphQL/ValidArgumentNameSniff.php b/Magento2/Sniffs/GraphQL/ValidArgumentNameSniff.php
index ffb1f8d4..03de433f 100644
--- a/Magento2/Sniffs/GraphQL/ValidArgumentNameSniff.php
+++ b/Magento2/Sniffs/GraphQL/ValidArgumentNameSniff.php
@@ -3,6 +3,7 @@
  * Copyright © Magento. All rights reserved.
  * See COPYING.txt for license details.
  */
+
 namespace Magento2\Sniffs\GraphQL;
 
 use PHP_CodeSniffer\Files\File;
@@ -64,7 +65,7 @@ public function process(File $phpcsFile, $stackPtr)
     }
 
     /**
-     * Finds all argument names contained in <var>$tokens</var> range <var>$startPointer</var> and
+     * Finds all argument names contained in <var>$tokens</var> in range <var>$startPointer</var> to
      * <var>$endPointer</var>.
      *
      * @param int $startPointer
@@ -80,7 +81,7 @@ private function getArguments($startPointer, $endPointer, array $tokens)
         $skipTypes            = [T_COMMENT, T_WHITESPACE];
 
         for ($i = $startPointer + 1; $i < $endPointer; ++$i) {
-            //skip comment tokens
+            //skip some tokens
             if (in_array($tokens[$i]['code'], $skipTypes)) {
                 continue;
             }
@@ -110,15 +111,6 @@ private function getArguments($startPointer, $endPointer, array $tokens)
      */
     private function getCloseParenthesisPointer($stackPointer, array $tokens)
     {
-        $numTokens = count($tokens);
-
-        for ($i = $stackPointer + 1; $i < $numTokens; ++$i) {
-            if ($tokens[$i]['code'] === T_CLOSE_PARENTHESIS) {
-                return $i;
-            }
-        }
-
-        //if we came here we could not find the closing parenthesis
-        return false;
+        return $this->seekToken(T_CLOSE_PARENTHESIS, $tokens, $stackPointer);
     }
 }
diff --git a/Magento2/Sniffs/GraphQL/ValidEnumValueSniff.php b/Magento2/Sniffs/GraphQL/ValidEnumValueSniff.php
new file mode 100644
index 00000000..b7c702c7
--- /dev/null
+++ b/Magento2/Sniffs/GraphQL/ValidEnumValueSniff.php
@@ -0,0 +1,134 @@
+<?php
+/**
+ * Copyright © Magento. All rights reserved.
+ * See COPYING.txt for license details.
+ */
+namespace Magento2\Sniffs\GraphQL;
+
+use PHP_CodeSniffer\Files\File;
+
+/**
+ * Detects enum values that are not specified in <kbd>SCREAMING_SNAKE_CASE</kbd>.
+ */
+class ValidEnumValueSniff extends AbstractGraphQLSniff
+{
+
+    /**
+     * @inheritDoc
+     */
+    public function register()
+    {
+        return [T_CLASS];
+    }
+
+    /**
+     * @inheritDoc
+     */
+    public function process(File $phpcsFile, $stackPtr)
+    {
+        $tokens = $phpcsFile->getTokens();
+
+        //bail out if we're not inspecting an enum
+        if ($tokens[$stackPtr]['content'] !== 'enum') {
+            return;
+        }
+
+        $openingCurlyPointer = $this->getOpeningCurlyBracketPointer($stackPtr, $tokens);
+        $closingCurlyPointer = $this->getClosingCurlyBracketPointer($stackPtr, $tokens);
+
+        //if we could not find the closing curly bracket pointer, we add a warning and terminate
+        if ($openingCurlyPointer === false || $closingCurlyPointer === false) {
+            $error = 'Possible parse error: %s missing opening or closing brace';
+            $data  = [$tokens[$stackPtr]['content']];
+            $phpcsFile->addWarning($error, $stackPtr, 'MissingBrace', $data);
+            return;
+        }
+
+        $values = $this->getValues($openingCurlyPointer, $closingCurlyPointer, $tokens, $phpcsFile->eolChar);
+
+        foreach ($values as $value) {
+            $pointer = $value[0];
+            $name    = $value[1];
+
+            if (!$this->isSnakeCase($name, true)) {
+                $type  = 'Enum value';
+                $error = '%s "%s" is not in SCREAMING_SNAKE_CASE format';
+                $data  = [
+                    $type,
+                    $name,
+                ];
+
+                $phpcsFile->addError($error, $pointer, 'NotScreamingSnakeCase', $data);
+                $phpcsFile->recordMetric($pointer, 'SCREAMING_SNAKE_CASE enum value', 'no');
+            } else {
+                $phpcsFile->recordMetric($pointer, 'SCREAMING_SNAKE_CASE enum value', 'yes');
+            }
+        }
+
+        return $closingCurlyPointer;
+    }
+
+    /**
+     * Seeks the next available token of type {@link T_CLOSE_CURLY_BRACKET} in <var>$tokens</var> and returns its
+     * pointer.
+     *
+     * @param int $startPointer
+     * @param array $tokens
+     * @return bool|int
+     */
+    private function getClosingCurlyBracketPointer($startPointer, array $tokens)
+    {
+        return $this->seekToken(T_CLOSE_CURLY_BRACKET, $tokens, $startPointer);
+    }
+
+    /**
+     * Seeks the next available token of type {@link T_OPEN_CURLY_BRACKET} in <var>$tokens</var> and returns its
+     * pointer.
+     *
+     * @param $startPointer
+     * @param array $tokens
+     * @return bool|int
+     */
+    private function getOpeningCurlyBracketPointer($startPointer, array $tokens)
+    {
+        return $this->seekToken(T_OPEN_CURLY_BRACKET, $tokens, $startPointer);
+    }
+
+    /**
+     * Finds all enum values contained in <var>$tokens</var> in range <var>$startPointer</var> to
+     * <var>$endPointer</var>.
+     *
+     * @param int $startPointer
+     * @param int $endPointer
+     * @param array $tokens
+     * @param string $eolChar
+     * @return array[]
+     */
+    private function getValues($startPointer, $endPointer, array $tokens, $eolChar)
+    {
+        $valueTokenPointer = null;
+        $enumValue         = '';
+        $values            = [];
+        $skipTypes         = [T_COMMENT, T_WHITESPACE];
+
+        for ($i = $startPointer + 1; $i < $endPointer; ++$i) {
+            //skip some tokens
+            if (in_array($tokens[$i]['code'], $skipTypes)) {
+                continue;
+            }
+            $enumValue .= $tokens[$i]['content'];
+
+            if ($valueTokenPointer === null) {
+                $valueTokenPointer = $i;
+            }
+
+            if (strpos($enumValue, $eolChar) !== false) {
+                $values[]          = [$valueTokenPointer, rtrim($enumValue, $eolChar)];
+                $enumValue         = '';
+                $valueTokenPointer = null;
+            }
+        }
+
+        return $values;
+    }
+}
diff --git a/Magento2/Tests/GraphQL/ValidEnumValueUnitTest.graphqls b/Magento2/Tests/GraphQL/ValidEnumValueUnitTest.graphqls
new file mode 100644
index 00000000..994e75f2
--- /dev/null
+++ b/Magento2/Tests/GraphQL/ValidEnumValueUnitTest.graphqls
@@ -0,0 +1,19 @@
+enum Foo {
+    # Valid values
+    VALID_SCREAMING_SNAKE_CASE_VALUE
+    VALID_SCREAMING_SNAKE_CASE_VALUE_WITH_1_NUMBER
+    VALID_SCREAMING_SNAKE_CASE_VALUE_WITH_12345_NUMBERS
+    VALID_SCREAMING_SNAKE_CASE_VALUE_ENDING_WITH_NUMBER_5
+    VALIDUPPERCASEVALUE
+
+    # Invalid values
+    1_INVALID_SCREAMING_SNAKE_CASE_VALUE_STARTING_WITH_NUMBER
+    invalidCamelCaseValue
+    InvalidCamelCaseCapsValue
+    invalidlowercasevalue
+}
+
+# Ignored although it triggers a T_CLASS token
+type Bar {
+    some_field: String
+}
\ No newline at end of file
diff --git a/Magento2/Tests/GraphQL/ValidEnumValueUnitTest.php b/Magento2/Tests/GraphQL/ValidEnumValueUnitTest.php
new file mode 100644
index 00000000..9d577f68
--- /dev/null
+++ b/Magento2/Tests/GraphQL/ValidEnumValueUnitTest.php
@@ -0,0 +1,34 @@
+<?php
+/**
+ * Copyright © Magento. All rights reserved.
+ * See COPYING.txt for license details.
+ */
+
+namespace Magento2\Tests\GraphQL;
+
+/**
+ * Covers {@link \Magento2\Sniffs\GraphQL\ValidEnumValueSniff}
+ */
+class ValidEnumValueUnitTest extends AbstractGraphQLSniffUnitTestCase
+{
+    /**
+     * @inheritDoc
+     */
+    protected function getErrorList()
+    {
+        return [
+            10 => 1,
+            11 => 1,
+            12 => 1,
+            13 => 1,
+        ];
+    }
+
+    /**
+     * @inheritDoc
+     */
+    protected function getWarningList()
+    {
+        return [];
+    }
+}