diff --git a/completions/rbenv.fish b/completions/rbenv.fish
new file mode 100644
index 00000000..3ca8e945
--- /dev/null
+++ b/completions/rbenv.fish
@@ -0,0 +1,22 @@
+function __fish_rbenv_needs_command
+  set cmd (commandline -opc)
+  if [ (count $cmd) -eq 1 -a $cmd[1] = 'rbenv' ]
+    return 0
+  end
+  return 1
+end
+
+function __fish_rbenv_using_command
+  set cmd (commandline -opc)
+  if [ (count $cmd) -gt 1 ]
+    if [ $argv[1] = $cmd[2] ]
+      return 0
+    end
+  end
+  return 1
+end
+
+complete -f -c rbenv -n '__fish_rbenv_needs_command' -a '(rbenv commands)'
+for cmd in (rbenv commands)
+  complete -f -c rbenv -n "__fish_rbenv_using_command $cmd" -a "(rbenv completions $cmd)"
+end
diff --git a/libexec/rbenv-init b/libexec/rbenv-init
index 2dbd67d1..c3a3bb02 100755
--- a/libexec/rbenv-init
+++ b/libexec/rbenv-init
@@ -62,6 +62,9 @@ if [ -z "$print" ]; then
   ksh )
     profile='~/.profile'
     ;;
+  fish )
+    profile='~/.config/fish/config.fish'
+    ;;
   * )
     profile='your profile'
     ;;
@@ -80,7 +83,14 @@ fi
 mkdir -p "${RBENV_ROOT}/"{shims,versions}
 
 if [[ ":${PATH}:" != *:"${RBENV_ROOT}/shims":* ]]; then
-  echo 'export PATH="'${RBENV_ROOT}'/shims:${PATH}"'
+  case "$shell" in
+  fish )
+    echo 'setenv PATH "'${RBENV_ROOT}'/shims"' '$PATH' ';'
+  ;;
+  * )
+    echo 'export PATH="'${RBENV_ROOT}'/shims:${PATH}"'
+  ;;
+  esac
 fi
 
 completion="${root}/completions/rbenv.${shell}"
@@ -91,8 +101,27 @@ if [ -z "$no_rehash" ]; then
 fi
 
 commands=(`rbenv-commands --sh`)
-IFS="|"
-cat <<EOS
+case "$shell" in
+fish )
+  cat <<EOS
+function rbenv
+  set command \$argv[1]
+  if [ (count \$argv) -gt 0 ]
+    set -e argv[1]
+  end
+
+  switch "\$command"
+  case ${commands[*]}
+    eval (rbenv "sh-\$command" \$argv)
+  case '*'
+    command rbenv "\$command" \$argv
+  end
+end
+EOS
+  ;;
+* )
+  IFS="|"
+  cat <<EOS
 rbenv() {
   typeset command
   command="\$1"
@@ -108,3 +137,5 @@ rbenv() {
   esac
 }
 EOS
+  ;;
+esac
diff --git a/libexec/rbenv-sh-rehash b/libexec/rbenv-sh-rehash
index 7548861b..9ec290dc 100755
--- a/libexec/rbenv-sh-rehash
+++ b/libexec/rbenv-sh-rehash
@@ -7,7 +7,17 @@ if [ "$1" = "--complete" ]; then
   exec rbenv-rehash --complete
 fi
 
+shell="$(basename "$SHELL")"
+
 # When rbenv shell integration is enabled, delegate to rbenv-rehash,
 # then tell the shell to empty its command lookup cache.
 rbenv-rehash
-echo "hash -r 2>/dev/null || true"
+
+case "$shell" in
+fish )
+  # nothing to do
+  ;;
+* )
+  echo "hash -r 2>/dev/null || true"
+  ;;
+esac
diff --git a/libexec/rbenv-sh-shell b/libexec/rbenv-sh-shell
index 4b89c6c0..d0ffe1b0 100755
--- a/libexec/rbenv-sh-shell
+++ b/libexec/rbenv-sh-shell
@@ -24,6 +24,7 @@ if [ "$1" = "--complete" ]; then
 fi
 
 version="$1"
+shell="$(basename "$SHELL")"
 
 if [ -z "$version" ]; then
   if [ -z "$RBENV_VERSION" ]; then
@@ -36,14 +37,28 @@ if [ -z "$version" ]; then
 fi
 
 if [ "$version" = "--unset" ]; then
-  echo "unset RBENV_VERSION"
+  case "$shell" in
+  fish )
+    echo "set -e RBENV_VERSION"
+    ;;
+  * )
+    echo "unset RBENV_VERSION"
+    ;;
+  esac
   exit
 fi
 
 # Make sure the specified version is installed.
 if rbenv-prefix "$version" >/dev/null; then
-  echo "export RBENV_VERSION=\"${version}\""
+  case "$shell" in
+  fish )
+    echo "setenv RBENV_VERSION \"${version}\""
+    ;;
+  * )
+    echo "export RBENV_VERSION=\"${version}\""
+    ;;
+  esac
 else
-  echo "return 1"
+  echo "false"
   exit 1
 fi
diff --git a/test/init.bats b/test/init.bats
index dc9fe302..a4c63199 100644
--- a/test/init.bats
+++ b/test/init.bats
@@ -18,13 +18,19 @@ load test_helper
 }
 
 @test "setup shell completions" {
-  export SHELL=/bin/bash
   root="$(cd $BATS_TEST_DIRNAME/.. && pwd)"
-  run rbenv-init -
+  SHELL=/bin/bash run rbenv-init -
   assert_success
   assert_line "source '${root}/libexec/../completions/rbenv.bash'"
 }
 
+@test "setup shell completions (fish)" {
+  root="$(cd $BATS_TEST_DIRNAME/.. && pwd)"
+  SHELL=/usr/bin/fish run rbenv-init -
+  assert_success
+  assert_line '. "'${root}'/libexec/../completions/rbenv.fish";'
+}
+
 @test "option to skip rehash" {
   run rbenv-init - --no-rehash
   assert_success
@@ -33,14 +39,28 @@ load test_helper
 
 @test "adds shims to PATH" {
   export PATH="${BATS_TEST_DIRNAME}/../libexec:/usr/bin:/bin"
-  run rbenv-init -
+  SHELL=/bin/bash run rbenv-init -
   assert_success
   assert_line 0 'export PATH="'${RBENV_ROOT}'/shims:${PATH}"'
 }
 
+@test "adds shims to PATH (fish)" {
+  export PATH="${BATS_TEST_DIRNAME}/../libexec:/usr/bin:/bin"
+  SHELL=/usr/bin/fish run rbenv-init -
+  assert_success
+  assert_line 0 'setenv PATH "'${RBENV_ROOT}'/shims" $PATH ;'
+}
+
 @test "doesn't add shims to PATH more than once" {
   export PATH="${RBENV_ROOT}/shims:$PATH"
-  run rbenv-init -
+  SHELL=/bin/bash run rbenv-init -
   assert_success
   refute_line 'export PATH="'${RBENV_ROOT}'/shims:${PATH}"'
 }
+
+@test "doesn't add shims to PATH more than once (fish)" {
+  export PATH="${RBENV_ROOT}/shims:$PATH"
+  SHELL=/usr/bin/fish run rbenv-init -
+  assert_success
+  refute_line 'setenv PATH "'${RBENV_ROOT}'/shims" $PATH ;'
+}
diff --git a/test/shell.bats b/test/shell.bats
index 579d31ae..b14d1cfb 100644
--- a/test/shell.bats
+++ b/test/shell.bats
@@ -11,26 +11,42 @@ load test_helper
 }
 
 @test "shell version" {
-  RBENV_VERSION="1.2.3" run rbenv-sh-shell
+  SHELL=/bin/bash RBENV_VERSION="1.2.3" run rbenv-sh-shell
+  assert_success 'echo "$RBENV_VERSION"'
+}
+
+@test "shell version (fish)" {
+  SHELL=/usr/bin/fish RBENV_VERSION="1.2.3" run rbenv-sh-shell
   assert_success 'echo "$RBENV_VERSION"'
 }
 
 @test "shell unset" {
-  run rbenv-sh-shell --unset
+  SHELL=/bin/bash run rbenv-sh-shell --unset
   assert_success "unset RBENV_VERSION"
 }
 
+@test "shell unset (fish)" {
+  SHELL=/usr/bin/fish run rbenv-sh-shell --unset
+  assert_success "set -e RBENV_VERSION"
+}
+
 @test "shell change invalid version" {
   run rbenv-sh-shell 1.2.3
   assert_failure
   assert_output <<SH
 rbenv: version \`1.2.3' not installed
-return 1
+false
 SH
 }
 
 @test "shell change version" {
   mkdir -p "${RBENV_ROOT}/versions/1.2.3"
-  run rbenv-sh-shell 1.2.3
+  SHELL=/bin/bash run rbenv-sh-shell 1.2.3
   assert_success 'export RBENV_VERSION="1.2.3"'
 }
+
+@test "shell change version (fish)" {
+  mkdir -p "${RBENV_ROOT}/versions/1.2.3"
+  SHELL=/usr/bin/fish run rbenv-sh-shell 1.2.3
+  assert_success 'setenv RBENV_VERSION "1.2.3"'
+}