diff --git a/pygments/lexers/fortran.py b/pygments/lexers/fortran.py
index e0619c7f58..4396735655 100644
--- a/pygments/lexers/fortran.py
+++ b/pygments/lexers/fortran.py
@@ -61,9 +61,9 @@ class FortranLexer(RegexLexer):
                 'FUNCTION', 'GENERIC', 'GOTO', 'IF', 'IMAGES', 'IMPLICIT',
                 'IMPORT', 'IMPURE', 'INCLUDE', 'INQUIRE', 'INTENT', 'INTERFACE',
                 'INTRINSIC', 'IS', 'LOCK', 'MEMORY', 'MODULE', 'NAMELIST', 'NULLIFY',
-                'NONE', 'NON_INTRINSIC', 'NON_OVERRIDABLE', 'NOPASS', 'OPEN', 'OPTIONAL',
-                'OPTIONS', 'PARAMETER', 'PASS', 'PAUSE', 'POINTER', 'PRINT', 'PRIVATE',
-                'PROGRAM', 'PROCEDURE', 'PROTECTED', 'PUBLIC', 'PURE', 'READ',
+                'NONE', 'NON_INTRINSIC', 'NON_OVERRIDABLE', 'NOPASS', 'ONLY', 'OPEN', 
+                'OPTIONAL', 'OPTIONS', 'PARAMETER', 'PASS', 'PAUSE', 'POINTER', 'PRINT', 
+                'PRIVATE', 'PROGRAM', 'PROCEDURE', 'PROTECTED', 'PUBLIC', 'PURE', 'READ',
                 'RECURSIVE', 'RESULT', 'RETURN', 'REWIND', 'SAVE', 'SELECT', 'SEQUENCE',
                 'STOP', 'SUBMODULE', 'SUBROUTINE', 'SYNC', 'SYNCALL', 'SYNCIMAGES',
                 'SYNCMEMORY', 'TARGET', 'THEN', 'TYPE', 'UNLOCK', 'USE', 'VALUE',