diff --git a/config/linux/aarch64/entrypoints.txt b/config/linux/aarch64/entrypoints.txt
index 8314df8..565fbf7 100644
--- a/config/linux/aarch64/entrypoints.txt
+++ b/config/linux/aarch64/entrypoints.txt
@@ -2,8 +2,12 @@
     # ctype.h entrypoints
     libc.src.ctype.isalnum
     libc.src.ctype.isalpha
+    libc.src.ctype.isblank
+    libc.src.ctype.iscntrl
     libc.src.ctype.isdigit
+    libc.src.ctype.isgraph
     libc.src.ctype.islower
+    libc.src.ctype.ispunct
     libc.src.ctype.isupper
     
     # errno.h entrypoints
diff --git a/config/linux/api.td b/config/linux/api.td
index 03d5d66..a57c703 100644
--- a/config/linux/api.td
+++ b/config/linux/api.td
@@ -90,8 +90,12 @@
   let Functions = [
     "isalnum",
     "isalpha",
+    "isblank",
+    "iscntrl",
     "isdigit",
+    "isgraph",
     "islower",
+    "ispunct",
     "isupper",
   ];
 }
diff --git a/config/linux/x86_64/entrypoints.txt b/config/linux/x86_64/entrypoints.txt
index 56a99d0..3cc243e 100644
--- a/config/linux/x86_64/entrypoints.txt
+++ b/config/linux/x86_64/entrypoints.txt
@@ -5,8 +5,12 @@
     # ctype.h entrypoints
     libc.src.ctype.isalnum
     libc.src.ctype.isalpha
+    libc.src.ctype.isblank
+    libc.src.ctype.iscntrl
     libc.src.ctype.isdigit
+    libc.src.ctype.isgraph
     libc.src.ctype.islower
+    libc.src.ctype.ispunct
     libc.src.ctype.isupper
 
     # errno.h entrypoints
diff --git a/spec/stdc.td b/spec/stdc.td
index 4fffc5c..1f14f76 100644
--- a/spec/stdc.td
+++ b/spec/stdc.td
@@ -57,16 +57,36 @@
               [ArgSpec<IntType>]
           >,
           FunctionSpec<
+              "isblank",
+              RetValSpec<IntType>,
+              [ArgSpec<IntType>]
+          >,
+          FunctionSpec<
+              "iscntrl",
+              RetValSpec<IntType>,
+              [ArgSpec<IntType>]
+          >,
+          FunctionSpec<
               "isdigit",
               RetValSpec<IntType>,
               [ArgSpec<IntType>]
           >,
           FunctionSpec<
+              "isgraph",
+              RetValSpec<IntType>,
+              [ArgSpec<IntType>]
+          >,
+          FunctionSpec<
               "islower",
               RetValSpec<IntType>,
               [ArgSpec<IntType>]
           >,
           FunctionSpec<
+              "ispunct",
+              RetValSpec<IntType>,
+              [ArgSpec<IntType>]
+          >,
+          FunctionSpec<
               "isupper",
               RetValSpec<IntType>,
               [ArgSpec<IntType>]
diff --git a/src/ctype/CMakeLists.txt b/src/ctype/CMakeLists.txt
index 30995ab..c554e6c 100644
--- a/src/ctype/CMakeLists.txt
+++ b/src/ctype/CMakeLists.txt
@@ -25,6 +25,22 @@
 )
 
 add_entrypoint_object(
+  isblank
+  SRCS
+    isblank.cpp
+  HDRS
+    isblank.h
+)
+
+add_entrypoint_object(
+  iscntrl
+  SRCS
+    iscntrl.cpp
+  HDRS
+    iscntrl.h
+)
+
+add_entrypoint_object(
   isdigit
   SRCS
     isdigit.cpp
@@ -35,6 +51,16 @@
 )
 
 add_entrypoint_object(
+  isgraph
+  SRCS
+    isgraph.cpp
+  HDRS
+    isgraph.h
+  DEPENDS
+    .ctype_utils
+)
+
+add_entrypoint_object(
   islower
   SRCS
     islower.cpp
@@ -43,6 +69,16 @@
 )
 
 add_entrypoint_object(
+  ispunct
+  SRCS
+    ispunct.cpp
+  HDRS
+    ispunct.h
+  DEPENDS
+    .ctype_utils
+)
+
+add_entrypoint_object(
   isupper
   SRCS
     isupper.cpp
diff --git a/src/ctype/ctype_utils.h b/src/ctype/ctype_utils.h
index 4e8d396..787a19e 100644
--- a/src/ctype/ctype_utils.h
+++ b/src/ctype/ctype_utils.h
@@ -18,15 +18,13 @@
 // of a function call by inlining them.
 // ------------------------------------------------------
 
-static inline int isdigit(int c) {
-  const unsigned ch = c;
-  return (ch - '0') < 10;
-}
+static inline int isdigit(unsigned ch) { return (ch - '0') < 10; }
 
-static inline int isalpha(int c) {
-  const unsigned ch = c;
-  return (ch | 32) - 'a' < 26;
-}
+static inline int isalpha(unsigned ch) { return (ch | 32) - 'a' < 26; }
+
+static inline int isalnum(unsigned ch) { return isalpha(ch) || isdigit(ch); }
+
+static inline int isgraph(unsigned ch) { return 0x20 < ch && ch < 0x7f; }
 
 } // namespace internal
 } // namespace __llvm_libc
diff --git a/src/ctype/isalnum.cpp b/src/ctype/isalnum.cpp
index 08b6520..54c4f80 100644
--- a/src/ctype/isalnum.cpp
+++ b/src/ctype/isalnum.cpp
@@ -15,8 +15,6 @@
 
 // TODO: Currently restricted to default locale.
 // These should be extended using locale information.
-int LLVM_LIBC_ENTRYPOINT(isalnum)(int c) {
-  return internal::isalpha(c) || internal::isdigit(c);
-}
+int LLVM_LIBC_ENTRYPOINT(isalnum)(int c) { return internal::isalnum(c); }
 
 } // namespace __llvm_libc
diff --git a/src/ctype/isblank.cpp b/src/ctype/isblank.cpp
new file mode 100644
index 0000000..fa28d84
--- /dev/null
+++ b/src/ctype/isblank.cpp
@@ -0,0 +1,22 @@
+//===-- Implementation of isblank------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#include "src/ctype/isblank.h"
+
+#include "src/__support/common.h"
+
+namespace __llvm_libc {
+
+// TODO: Currently restricted to default locale.
+// These should be extended using locale information.
+int LLVM_LIBC_ENTRYPOINT(isblank)(int c) {
+  const unsigned char ch = c;
+  return ch == ' ' || ch == '\t';
+}
+
+} // namespace __llvm_libc
diff --git a/src/ctype/isblank.h b/src/ctype/isblank.h
new file mode 100644
index 0000000..0554322
--- /dev/null
+++ b/src/ctype/isblank.h
@@ -0,0 +1,18 @@
+//===-- Implementation header for isblank -------------------------*-C++-*-===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_LIBC_SRC_CTYPE_ISBLANK_H
+#define LLVM_LIBC_SRC_CTYPE_ISBLANK_H
+
+namespace __llvm_libc {
+
+int isblank(int c);
+
+} // namespace __llvm_libc
+
+#endif //  LLVM_LIBC_SRC_CTYPE_ISBLANK_H
diff --git a/src/ctype/iscntrl.cpp b/src/ctype/iscntrl.cpp
new file mode 100644
index 0000000..06ee7cc
--- /dev/null
+++ b/src/ctype/iscntrl.cpp
@@ -0,0 +1,22 @@
+//===-- Implementation of iscntrl------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#include "src/ctype/iscntrl.h"
+
+#include "src/__support/common.h"
+
+namespace __llvm_libc {
+
+// TODO: Currently restricted to default locale.
+// These should be extended using locale information.
+int LLVM_LIBC_ENTRYPOINT(iscntrl)(int c) {
+  const unsigned char ch = c;
+  return ch < 0x20 || ch == 0x7f;
+}
+
+} // namespace __llvm_libc
diff --git a/src/ctype/iscntrl.h b/src/ctype/iscntrl.h
new file mode 100644
index 0000000..26f0940
--- /dev/null
+++ b/src/ctype/iscntrl.h
@@ -0,0 +1,18 @@
+//===-- Implementation header for iscntrl -------------------------*-C++-*-===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_LIBC_SRC_CTYPE_ISCNTRL_H
+#define LLVM_LIBC_SRC_CTYPE_ISCNTRL_H
+
+namespace __llvm_libc {
+
+int iscntrl(int c);
+
+} // namespace __llvm_libc
+
+#endif //  LLVM_LIBC_SRC_CTYPE_ISCNTRL_H
diff --git a/src/ctype/isgraph.cpp b/src/ctype/isgraph.cpp
new file mode 100644
index 0000000..c7a488c
--- /dev/null
+++ b/src/ctype/isgraph.cpp
@@ -0,0 +1,20 @@
+//===-- Implementation of isgraph------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#include "src/ctype/isgraph.h"
+
+#include "src/__support/common.h"
+#include "src/ctype/ctype_utils.h"
+
+namespace __llvm_libc {
+
+// TODO: Currently restricted to default locale.
+// These should be extended using locale information.
+int LLVM_LIBC_ENTRYPOINT(isgraph)(int c) { return internal::isgraph(c); }
+
+} // namespace __llvm_libc
diff --git a/src/ctype/isgraph.h b/src/ctype/isgraph.h
new file mode 100644
index 0000000..421d0ff
--- /dev/null
+++ b/src/ctype/isgraph.h
@@ -0,0 +1,18 @@
+//===-- Implementation header for isgraph -------------------------*-C++-*-===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_LIBC_SRC_CTYPE_ISGRAPH_H
+#define LLVM_LIBC_SRC_CTYPE_ISGRAPH_H
+
+namespace __llvm_libc {
+
+int isgraph(int c);
+
+} // namespace __llvm_libc
+
+#endif //  LLVM_LIBC_SRC_CTYPE_ISGRAPH_H
diff --git a/src/ctype/ispunct.cpp b/src/ctype/ispunct.cpp
new file mode 100644
index 0000000..a810c64
--- /dev/null
+++ b/src/ctype/ispunct.cpp
@@ -0,0 +1,22 @@
+//===-- Implementation of ispunct------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#include "src/ctype/ispunct.h"
+
+#include "src/__support/common.h"
+#include "src/ctype/ctype_utils.h"
+
+namespace __llvm_libc {
+
+// TODO: Currently restricted to default locale.
+// These should be extended using locale information.
+int LLVM_LIBC_ENTRYPOINT(ispunct)(int c) {
+  return !internal::isalnum(c) && internal::isgraph(c);
+}
+
+} // namespace __llvm_libc
diff --git a/src/ctype/ispunct.h b/src/ctype/ispunct.h
new file mode 100644
index 0000000..23cc08a
--- /dev/null
+++ b/src/ctype/ispunct.h
@@ -0,0 +1,18 @@
+//===-- Implementation header for ispunct -------------------------*-C++-*-===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_LIBC_SRC_CTYPE_ISPUNCT_H
+#define LLVM_LIBC_SRC_CTYPE_ISPUNCT_H
+
+namespace __llvm_libc {
+
+int ispunct(int c);
+
+} // namespace __llvm_libc
+
+#endif //  LLVM_LIBC_SRC_CTYPE_ISPUNCT_H
diff --git a/test/src/ctype/CMakeLists.txt b/test/src/ctype/CMakeLists.txt
index c995946..3adf573 100644
--- a/test/src/ctype/CMakeLists.txt
+++ b/test/src/ctype/CMakeLists.txt
@@ -21,6 +21,26 @@
 )
 
 add_libc_unittest(
+  isblank
+  SUITE
+    libc_ctype_unittests
+  SRCS
+    isblank_test.cpp
+  DEPENDS
+    libc.src.ctype.isblank
+)
+
+add_libc_unittest(
+  iscntrl
+  SUITE
+    libc_ctype_unittests
+  SRCS
+    iscntrl_test.cpp
+  DEPENDS
+    libc.src.ctype.iscntrl
+)
+
+add_libc_unittest(
   isdigit
   SUITE
     libc_ctype_unittests
@@ -31,6 +51,16 @@
 )
 
 add_libc_unittest(
+  isgraph
+  SUITE
+    libc_ctype_unittests
+  SRCS
+    isgraph_test.cpp
+  DEPENDS
+    libc.src.ctype.isgraph
+)
+
+add_libc_unittest(
   islower
   SUITE
     libc_ctype_unittests
@@ -41,6 +71,16 @@
 )
 
 add_libc_unittest(
+  ispunct
+  SUITE
+    libc_ctype_unittests
+  SRCS
+    ispunct_test.cpp
+  DEPENDS
+    libc.src.ctype.ispunct
+)
+
+add_libc_unittest(
   isupper
   SUITE
     libc_ctype_unittests
diff --git a/test/src/ctype/isblank_test.cpp b/test/src/ctype/isblank_test.cpp
new file mode 100644
index 0000000..f024ef6
--- /dev/null
+++ b/test/src/ctype/isblank_test.cpp
@@ -0,0 +1,21 @@
+//===-- Unittests for isblank----------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#include "src/ctype/isblank.h"
+#include "utils/UnitTest/Test.h"
+
+TEST(IsBlank, DefaultLocale) {
+  // Loops through all characters, verifying that space and horizontal tab
+  // return a non-zero integer and everything else returns zero.
+  for (int ch = 0; ch < 255; ++ch) {
+    if (ch == ' ' || ch == '\t')
+      EXPECT_NE(__llvm_libc::isblank(ch), 0);
+    else
+      EXPECT_EQ(__llvm_libc::isblank(ch), 0);
+  }
+}
diff --git a/test/src/ctype/iscntrl_test.cpp b/test/src/ctype/iscntrl_test.cpp
new file mode 100644
index 0000000..5af7457
--- /dev/null
+++ b/test/src/ctype/iscntrl_test.cpp
@@ -0,0 +1,21 @@
+//===-- Unittests for iscntrl----------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#include "src/ctype/iscntrl.h"
+#include "utils/UnitTest/Test.h"
+
+TEST(IsCntrl, DefaultLocale) {
+  // Loops through all characters, verifying that control characters
+  // return a non-zero integer, all others return zero.
+  for (int ch = 0; ch < 255; ++ch) {
+    if ((0 <= ch && ch <= 0x1f /*US*/) || ch == 0x7f /*DEL*/)
+      EXPECT_NE(__llvm_libc::iscntrl(ch), 0);
+    else
+      EXPECT_EQ(__llvm_libc::iscntrl(ch), 0);
+  }
+}
diff --git a/test/src/ctype/isgraph_test.cpp b/test/src/ctype/isgraph_test.cpp
new file mode 100644
index 0000000..1ed1ec7
--- /dev/null
+++ b/test/src/ctype/isgraph_test.cpp
@@ -0,0 +1,21 @@
+//===-- Unittests for isgraph----------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#include "src/ctype/isgraph.h"
+#include "utils/UnitTest/Test.h"
+
+TEST(IsGraph, DefaultLocale) {
+  // Loops through all characters, verifying that graphical characters
+  // return a non-zero integer, everything else returns zero.
+  for (int ch = 0; ch < 255; ++ch) {
+    if ('!' <= ch && ch <= '~') // A-Z, a-z, 0-9, punctuation.
+      EXPECT_NE(__llvm_libc::isgraph(ch), 0);
+    else
+      EXPECT_EQ(__llvm_libc::isgraph(ch), 0);
+  }
+}
diff --git a/test/src/ctype/ispunct_test.cpp b/test/src/ctype/ispunct_test.cpp
new file mode 100644
index 0000000..07e83fb
--- /dev/null
+++ b/test/src/ctype/ispunct_test.cpp
@@ -0,0 +1,34 @@
+//===-- Unittests for ispunct----------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#include "src/ctype/ispunct.h"
+#include "utils/UnitTest/Test.h"
+
+// Helper function to mark the sections of the ASCII table that are
+// punctuation characters. These are listed below:
+//  Decimal    |         Symbol
+//  -----------------------------------------
+//  33 -  47   |  ! " $ % & ' ( ) * + , - . /
+//  58 -  64   |  : ; < = > ? @
+//  91 -  96   |  [ \ ] ^ _ `
+// 123 - 126   |  { | } ~
+static inline int is_punctuation_character(int c) {
+  return ('!' <= c && c <= '/') || (':' <= c && c <= '@') ||
+         ('[' <= c && c <= '`') || ('{' <= c && c <= '~');
+}
+
+TEST(IsPunct, DefaultLocale) {
+  // Loops through all characters, verifying that punctuation characters
+  // return a non-zero integer, and everything else returns zero.
+  for (int ch = 0; ch < 255; ++ch) {
+    if (is_punctuation_character(ch))
+      EXPECT_NE(__llvm_libc::ispunct(ch), 0);
+    else
+      EXPECT_EQ(__llvm_libc::ispunct(ch), 0);
+  }
+}