diff --git a/include/ctype.h b/include/ctype.h
index 67dc99e6e1..d3d62b53fd 100644
--- a/include/ctype.h
+++ b/include/ctype.h
@@ -134,6 +134,16 @@
 
 #define isalpha(c)   (islower(c) || isupper(c))
 
+/****************************************************************************
+ * Name: isblank
+ *
+ * Description:
+ *   Checks for blank characters (space or tab)
+ *
+ ****************************************************************************/
+
+#define isblank(c)   (isspace(c) || (c) == '\t')
+
 /****************************************************************************
  * Name: isdigit
  *
diff --git a/include/cxx/cctype b/include/cxx/cctype
index 604bc2c23d..36b62ca8c5 100644
--- a/include/cxx/cctype
+++ b/include/cxx/cctype
@@ -55,6 +55,7 @@
 #undef isprint
 #undef ispunct
 #undef isspace
+#undef isblank
 #undef isupper
 #undef isxdigit
 #undef tolower