diff --git a/.astyle/astyle-opts b/.astyle/astyle-opts
deleted file mode 100644
index 3bebecd61..000000000
--- a/.astyle/astyle-opts
+++ /dev/null
@@ -1,16 +0,0 @@
---style=allman
---max-code-length=120
---max-instatement-indent=100
---attach-namespaces --attach-inlines
---attach-extern-c
---min-conditional-indent=0
---break-blocks
---pad-oper
---pad-header
---unpad-paren
---align-pointer=name
---add-brackets
---keep-one-line-blocks
---convert-tabs
---break-after-logical
---formatted
diff --git a/.clang-format b/.clang-format
new file mode 100644
index 000000000..b5b25e775
--- /dev/null
+++ b/.clang-format
@@ -0,0 +1,112 @@
+---
+Language:        Cpp
+# BasedOnStyle:  LLVM
+AccessModifierOffset: -4
+AlignAfterOpenBracket: Align
+AlignConsecutiveAssignments: true
+AlignConsecutiveDeclarations: true
+AlignEscapedNewlines: Left
+AlignOperands:   true
+AlignTrailingComments: true
+AllowAllParametersOfDeclarationOnNextLine: false
+AllowShortBlocksOnASingleLine: false
+AllowShortCaseLabelsOnASingleLine: false
+AllowShortFunctionsOnASingleLine: InlineOnly
+AllowShortIfStatementsOnASingleLine: false
+AllowShortLoopsOnASingleLine: true
+AlwaysBreakAfterDefinitionReturnType: None
+AlwaysBreakAfterReturnType: None
+AlwaysBreakBeforeMultilineStrings: false
+AlwaysBreakTemplateDeclarations: false
+BinPackArguments: true
+BinPackParameters: false
+BraceWrapping:   
+  AfterClass:      true
+  AfterControlStatement: true
+  AfterEnum:       true
+  AfterFunction:   true
+  AfterNamespace:  false
+  AfterObjCDeclaration: false
+  AfterStruct:     true
+  AfterUnion:      true
+  BeforeCatch:     false
+  BeforeElse:      true
+  IndentBraces:    false
+  SplitEmptyFunction: true
+  SplitEmptyRecord: true
+  SplitEmptyNamespace: true
+BreakBeforeBinaryOperators: None
+BreakBeforeBraces: Custom
+BreakBeforeInheritanceComma: false
+BreakBeforeTernaryOperators: true
+BreakConstructorInitializersBeforeComma: false
+BreakConstructorInitializers: BeforeComma
+BreakAfterJavaFieldAnnotations: false
+BreakStringLiterals: true
+ColumnLimit:     120
+CommentPragmas:  '^ IWYU pragma:'
+CompactNamespaces: false
+ConstructorInitializerAllOnOneLineOrOnePerLine: false
+ConstructorInitializerIndentWidth: 4
+ContinuationIndentWidth: 4
+Cpp11BracedListStyle: true
+DerivePointerAlignment: false
+DisableFormat:   false
+ExperimentalAutoDetectBinPacking: false
+FixNamespaceComments: true
+ForEachMacros:   
+  - foreach
+  - Q_FOREACH
+  - BOOST_FOREACH
+IncludeCategories: 
+  - Regex:           '^<openthread/.*/'
+    Priority:        4
+  - Regex:           '^<openthread/'
+    Priority:        3
+  - Regex:           '^<'
+    Priority:        2
+  - Regex:           '^".*/'
+    Priority:        5
+  - Regex:           '^"'
+    Priority:        1
+IncludeIsMainRegex: '(Test)?$'
+IndentCaseLabels: false
+IndentWidth:     4
+IndentWrappedFunctionNames: false
+JavaScriptQuotes: Leave
+JavaScriptWrapImports: true
+KeepEmptyLinesAtTheStartOfBlocks: false
+MacroBlockBegin: ''
+MacroBlockEnd:   ''
+MaxEmptyLinesToKeep: 1
+NamespaceIndentation: None
+ObjCBlockIndentWidth: 2
+ObjCSpaceAfterProperty: false
+ObjCSpaceBeforeProtocolList: true
+PenaltyBreakAssignment: 2
+PenaltyBreakBeforeFirstCallParameter: 19
+PenaltyBreakComment: 300
+PenaltyBreakFirstLessLess: 120
+PenaltyBreakString: 1000
+PenaltyExcessCharacter: 1000000
+PenaltyReturnTypeOnItsOwnLine: 1000
+PointerAlignment: Right
+ReflowComments:  true
+SortIncludes:    true
+SortUsingDeclarations: true
+SpaceAfterCStyleCast: false
+SpaceAfterTemplateKeyword: true
+SpaceBeforeAssignmentOperators: true
+SpaceBeforeParens: ControlStatements
+SpaceInEmptyParentheses: false
+SpacesBeforeTrailingComments: 1
+SpacesInAngles:  false
+SpacesInContainerLiterals: true
+SpacesInCStyleCastParentheses: false
+SpacesInParentheses: false
+SpacesInSquareBrackets: false
+Standard:        Cpp11
+TabWidth:        4
+UseTab:          Never
+...
+
diff --git a/.travis.yml b/.travis.yml
index 4e73ae1f4..e47e55241 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -61,7 +61,13 @@ matrix:
       compiler: gcc
     - env: BUILD_TARGET="pretty-check"
       os: linux
-    - env: BUILD_TARGET="scan-build" CC=clang-5.0 CXX=clang++-5.0
+      addons:
+        apt:
+          sources:
+            - llvm-toolchain-trusty-5.0
+          packages:
+            - clang-5.0
+    - env: BUILD_TARGET="scan-build" CC="clang" CXX="clang++"
       os: linux
       addons:
         apt:
diff --git a/.travis/before_install.sh b/.travis/before_install.sh
index 6220dcfae..a9026991f 100755
--- a/.travis/before_install.sh
+++ b/.travis/before_install.sh
@@ -49,13 +49,7 @@ cd /tmp || die
     }
 
     [ $BUILD_TARGET != pretty-check ] || {
-        wget http://jaist.dl.sourceforge.net/project/astyle/astyle/astyle%202.05.1/astyle_2.05.1_linux.tar.gz || die
-        tar xzvf astyle_2.05.1_linux.tar.gz || die
-        cd astyle/build/gcc || die
-        LDFLAGS=" " make || die
-        cd ../../..
-        export PATH=/tmp/astyle/build/gcc/bin:$PATH || die
-        astyle --version || die
+        clang-format --version || die
     }
 
     [ $BUILD_TARGET != scan-build ] || {
diff --git a/.travis/script.sh b/.travis/script.sh
index d567af21d..7d6c972ff 100755
--- a/.travis/script.sh
+++ b/.travis/script.sh
@@ -35,7 +35,6 @@ die() {
 set -x
 
 [ $BUILD_TARGET != pretty-check ] || {
-    export PATH=/tmp/astyle/build/gcc/bin:$PATH || die
     ./bootstrap || die
     ./configure || die
     make pretty-check || die
diff --git a/Makefile.am b/Makefile.am
index 85658d9c5..d1c66248e 100644
--- a/Makefile.am
+++ b/Makefile.am
@@ -59,8 +59,6 @@ SUBDIRS                             = \
     $(NULL)
 
 EXTRA_DIST                          = \
-    .astyle/astyle-opts               \
-    .astyle/astyle-wrap.sh            \
     .default-version                  \
     bootstrap                         \
     etc                               \
diff --git a/configure.ac b/configure.ac
index 41288a1b7..d7634c751 100644
--- a/configure.ac
+++ b/configure.ac
@@ -357,10 +357,10 @@ fi
 # Code style
 #
 
-AC_SUBST(PRETTY, ["\${abs_top_srcdir}/.astyle/astyle-wrap.sh"])
-AC_SUBST(PRETTY_ARGS, ["astyle --options=\${abs_top_srcdir}/.astyle/astyle-opts"])
-AC_SUBST(PRETTY_CHECK, ["\${abs_top_srcdir}/.astyle/astyle-wrap.sh"])
-AC_SUBST(PRETTY_CHECK_ARGS, ["astyle --options=\${abs_top_srcdir}/.astyle/astyle-opts --dry-run"])
+AC_SUBST(PRETTY, ["clang-format"])
+AC_SUBST(PRETTY_ARGS, ["-style=file -i"])
+AC_SUBST(PRETTY_CHECK, ["\${abs_top_srcdir}/script/clang-format-check.sh"])
+AC_SUBST(PRETTY_CHECK_ARGS, [""])
 
 #
 # Tests
diff --git a/.astyle/astyle-wrap.sh b/script/clang-format-check.sh
similarity index 82%
rename from .astyle/astyle-wrap.sh
rename to script/clang-format-check.sh
index d530450a2..4d3df6c48 100755
--- a/.astyle/astyle-wrap.sh
+++ b/script/clang-format-check.sh
@@ -1,6 +1,6 @@
 #!/bin/sh
 #
-#  Copyright (c) 2016, The OpenThread Authors.
+#  Copyright (c) 2018, The OpenThread Authors.
 #  All rights reserved.
 #
 #  Redistribution and use in source and binary forms, with or without
@@ -28,17 +28,16 @@
 #
 
 #
-# astye does not return a non-zero exit code.  This wrapper exists with a
-# non-zero exit code if there is any output from astyle.
+# clang-format does not return a non-zero exit code.  This wrapper
+# exits with a non-zero exit code if clang-format outputs any
+# replacements.
 #
 
 die() {
-	echo " *** ERROR: " $*
-	exit 1
+    echo " *** ERROR: " $*
+    exit 1
 }
 
 set -x
 
-[ -z "`$@`" ] || {
-    [ "$3" != "--dry-run" ] || die
-}
+[ -z "`clang-format -style=file -output-replacements-xml $@ | grep \"<replacement \"`" ] || die