diff --git a/CHANGELOG.md b/CHANGELOG.md
index 99ff59a0..dd5a382a 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,5 +1,9 @@
 # Change Log
 
+## 9.0.0.1 - (In Progress)
+
+*  Add `iswblank` compatibility.
+
 ## 9.0.0 - 2016-12-28
 
 *  Update to Unicode Character Data 9.0.0.
diff --git a/README.md b/README.md
index 528d0ac8..ee0610f0 100644
--- a/README.md
+++ b/README.md
@@ -96,6 +96,7 @@ The following character classification functions are provided:
 |---------------|----------------|
 | `ucd_isalnum` | `ucd::isalnum` |
 | `ucd_isalpha` | `ucd::isalpha` |
+| `ucd_isblank` | `ucd::isblank` |
 | `ucd_iscntrl` | `ucd::iscntrl` |
 | `ucd_isdigit` | `ucd::isdigit` |
 | `ucd_isgraph` | `ucd::isgraph` |
@@ -105,7 +106,7 @@ The following character classification functions are provided:
 | `ucd_isspace` | `ucd::isspace` |
 | `ucd_isupper` | `ucd::isupper` |
 
-__NOTE:__ Equivalents for `isblank` and `isxdigit` are not provided.
+__NOTE:__ An equivalent for `isxdigit` is not provided.
 
 ## Build Dependencies
 
diff --git a/src/ctype.c b/src/ctype.c
index c4b63455..f1be7643 100644
--- a/src/ctype.c
+++ b/src/ctype.c
@@ -53,6 +53,19 @@ int ucd_isalpha(codepoint_t c)
 	}
 }
 
+int ucd_isblank(codepoint_t c)
+{
+	switch (ucd_lookup_category(c))
+	{
+	case UCD_CATEGORY_Zs:
+		return 1;
+	case UCD_CATEGORY_Cc:
+		return c == 0x09; // U+0009 : CHARACTER TABULATION
+	default:
+		return 0;
+	}
+}
+
 int ucd_iscntrl(codepoint_t c)
 {
 	return ucd_lookup_category(c) == UCD_CATEGORY_Cc;
diff --git a/src/include/ucd/ucd.h b/src/include/ucd/ucd.h
index cb87671b..ee415cc6 100644
--- a/src/include/ucd/ucd.h
+++ b/src/include/ucd/ucd.h
@@ -339,6 +339,13 @@ int ucd_isalnum(codepoint_t c);
   */
 int ucd_isalpha(codepoint_t c);
 
+/** @brief Is the codepoint a tab or Unicode whitespace character?
+  *
+  * @param c The Unicode codepoint to check.
+  * @return  Non-zero if the codepoint is a whitespace character, zero otherwise.
+  */
+int ucd_isblank(codepoint_t c);
+
 /** @brief Is the codepoint a control character?
   *
   * @param c The Unicode codepoint to check.
@@ -776,6 +783,16 @@ namespace ucd
 		return ucd_isalpha(c);
 	}
 
+	/** @brief Is the codepoint a tab or Unicode whitespace character?
+	  *
+	  * @param c The Unicode codepoint to check.
+	  * @return  Non-zero if the codepoint is a whitespace character, zero otherwise.
+	  */
+	inline int isblank(codepoint_t c)
+	{
+		return ucd_isblank(c);
+	}
+
 	/** @brief Is the codepoint a control character?
 	  *
 	  * @param c The Unicode codepoint to check.
diff --git a/tests/printcdata.c b/tests/printcdata.c
index 4b3b9b58..8b19749a 100644
--- a/tests/printcdata.c
+++ b/tests/printcdata.c
@@ -114,6 +114,9 @@ void uprintf_is(FILE *out, codepoint_t c, char mode)
 	case 'a': // alpha
 		fputc(iswalpha(c) ? '1' : '0', out);
 		break;
+	case 'b': // blank
+		fputc(iswblank(c) ? '1' : '0', out);
+		break;
 	case 'c': // control
 		fputc(iswcntrl(c) ? '1' : '0', out);
 		break;
diff --git a/tests/printucddata.c b/tests/printucddata.c
index 557b756c..9400b547 100644
--- a/tests/printucddata.c
+++ b/tests/printucddata.c
@@ -111,6 +111,9 @@ void uprintf_is(FILE *out, codepoint_t c, char mode)
 	case 'a': // alpha
 		fputc(ucd_isalpha(c) ? '1' : '0', out);
 		break;
+	case 'b': // blank
+		fputc(ucd_isblank(c) ? '1' : '0', out);
+		break;
 	case 'c': // control
 		fputc(ucd_iscntrl(c) ? '1' : '0', out);
 		break;
diff --git a/tests/printucddata_cpp.cpp b/tests/printucddata_cpp.cpp
index 77dffa52..41e37605 100644
--- a/tests/printucddata_cpp.cpp
+++ b/tests/printucddata_cpp.cpp
@@ -111,6 +111,9 @@ void uprintf_is(FILE *out, ucd::codepoint_t c, char mode)
 	case 'a': // alpha
 		fputc(ucd::isalpha(c) ? '1' : '0', out);
 		break;
+	case 'b': // blank
+		fputc(ucd::isblank(c) ? '1' : '0', out);
+		break;
 	case 'c': // control
 		fputc(ucd::iscntrl(c) ? '1' : '0', out);
 		break;