diff --git a/README.md b/README.md
index 186440a..067ab0c 100644
--- a/README.md
+++ b/README.md
@@ -71,6 +71,67 @@ source ~/.zshrc
 # または新しいターミナルを開く
 ```
 
+### シェル補完のセットアップ（オプション）
+
+タブ補完機能を使うと、コマンド入力が格段に便利になります:
+
+```bash
+bmc g <TAB>         # ブックマーク一覧を表示
+bmc g sam<TAB>      # 'sample-project' に補完
+bmc list --tag <TAB> # タグ一覧を表示
+```
+
+#### Bash
+
+`~/.bashrc` に以下を追加:
+
+```bash
+# bookmark-cli completion
+source ~/.local/share/bookmark-cli/completions/bmc.bash
+```
+
+設定を反映:
+```bash
+source ~/.bashrc
+```
+
+#### Zsh
+
+`~/.zshrc` に以下を追加:
+
+```bash
+# bookmark-cli completion
+fpath=(~/.local/share/bookmark-cli/completions $fpath)
+autoload -Uz compinit && compinit
+```
+
+設定を反映:
+```bash
+source ~/.zshrc
+```
+
+#### Fish
+
+補完ファイルをシンボリックリンク:
+
+```bash
+mkdir -p ~/.config/fish/completions
+ln -s ~/.local/share/bookmark-cli/completions/bmc.fish ~/.config/fish/completions/
+```
+
+Fishは次回起動時に自動的に補完を読み込みます。
+
+#### 補完機能の確認
+
+セットアップ後、以下でテスト:
+
+```bash
+bmc <TAB>            # 全コマンドを表示
+bmc g <TAB>          # ブックマーク一覧を表示
+bmc g sam<TAB>       # 'sample-project' に補完
+bmc list --tag <TAB> # タグ一覧を表示
+```
+
 ### 基本コマンド
 
 ```bash
diff --git a/completions/_bmc b/completions/_bmc
new file mode 100644
index 0000000..19057d4
--- /dev/null
+++ b/completions/_bmc
@@ -0,0 +1,123 @@
+#compdef bmc bm
+
+_bmc() {
+    local curcontext="$curcontext" state line
+    typeset -A opt_args
+
+    local -a commands
+    commands=(
+        'add:Add a bookmark for a directory'
+        'a:Alias for add'
+        'go:Navigate to a bookmarked directory'
+        'g:Alias for go'
+        'list:List all bookmarks'
+        'ls:Alias for list'
+        'tags:Show all tags'
+        'ui:Interactive UI with fzf'
+        'browse:Alias for ui'
+        'fz:Alias for ui'
+        'remove:Remove a bookmark'
+        'rm:Alias for remove'
+        'del:Alias for remove'
+        'rename:Rename a bookmark'
+        'mv:Alias for rename'
+        'export:Export bookmarks to JSON'
+        'exp:Alias for export'
+        'import:Import bookmarks from file'
+        'imp:Alias for import'
+        'edit:Edit bookmark file with $EDITOR'
+        'e:Alias for edit'
+        'validate:Validate all bookmarks'
+        'check:Alias for validate'
+        'clean:Remove invalid bookmarks'
+        'doctor:Show bookmark health diagnostic'
+        'recent:Show recently used bookmarks'
+        'r:Alias for recent'
+        'frequent:Show frequently used bookmarks'
+        'stats:Show bookmark usage statistics'
+        'help:Show help message'
+        'h:Alias for help'
+    )
+
+    _arguments -C \
+        '1: :->command' \
+        '*:: :->args'
+
+    case $state in
+        command)
+            _describe -t commands 'bmc commands' commands
+            ;;
+        args)
+            local cmd="${words[1]}"
+
+            # Normalize aliases
+            case "$cmd" in
+                a) cmd="add" ;;
+                g) cmd="go" ;;
+                ls) cmd="list" ;;
+                browse|fz) cmd="ui" ;;
+                rm|del) cmd="remove" ;;
+                mv) cmd="rename" ;;
+                exp) cmd="export" ;;
+                imp) cmd="import" ;;
+                e) cmd="edit" ;;
+                check) cmd="validate" ;;
+                r) cmd="recent" ;;
+                h) cmd="help" ;;
+            esac
+
+            case "$cmd" in
+                add)
+                    _arguments \
+                        '1:bookmark name:' \
+                        '2:path:_directories' \
+                        '(-d --description)'{-d,--description}'[Description]:description:' \
+                        '(-t --tags)'{-t,--tags}'[Tags (comma-separated)]:tags:'
+                    ;;
+                go|remove)
+                    _arguments '1:bookmark:_bmc_bookmarks'
+                    ;;
+                rename)
+                    _arguments \
+                        '1:old bookmark name:_bmc_bookmarks' \
+                        '2:new bookmark name:'
+                    ;;
+                list)
+                    _arguments '--tag[Filter by tag]:tag:_bmc_tags'
+                    ;;
+                clean)
+                    _arguments '--dry-run[Preview without removing]'
+                    ;;
+                import|export)
+                    _arguments '1:file:_files'
+                    ;;
+            esac
+            ;;
+    esac
+}
+
+_bmc_bookmarks() {
+    local -a bookmarks
+    local bmc_cmd="bmc"
+
+    command -v "$bmc_cmd" >/dev/null 2>&1 || return 1
+
+    bookmarks=(${(f)"$(NO_COLOR=1 $bmc_cmd list 2>/dev/null | \
+        awk 'NR > 2 && NF > 0 && $1 != "Tags:" { print $1 }')"})
+
+    _describe 'bookmarks' bookmarks
+}
+
+_bmc_tags() {
+    local -a tags
+    local bmc_cmd="bmc"
+
+    command -v "$bmc_cmd" >/dev/null 2>&1 || return 1
+
+    tags=(${(f)"$(NO_COLOR=1 $bmc_cmd tags 2>/dev/null | \
+        awk 'NF > 0 && $1 != "All" && $1 != "No" { print $1 }')"})
+
+    _describe 'tags' tags
+}
+
+_bmc "$@"
diff --git a/completions/bmc.bash b/completions/bmc.bash
new file mode 100644
index 0000000..926e4a0
--- /dev/null
+++ b/completions/bmc.bash
@@ -0,0 +1,101 @@
+#!/bin/bash
+# Bash completion for bmc (bookmark-cli)
+
+_bmc_completions() {
+    local cur prev words cword
+    _init_completion || return
+
+    cur="${COMP_WORDS[COMP_CWORD]}"
+    prev="${COMP_WORDS[COMP_CWORD-1]}"
+
+    # All commands (primary + aliases)
+    local commands="add a go g list ls tags ui browse fz remove rm del rename mv export exp import imp edit e validate check clean doctor recent r frequent stats help h"
+
+    # First argument: complete commands
+    if [ $COMP_CWORD -eq 1 ]; then
+        COMPREPLY=( $(compgen -W "$commands" -- "$cur") )
+        return 0
+    fi
+
+    # Get primary command
+    local cmd="${COMP_WORDS[1]}"
+
+    # Normalize aliases
+    case "$cmd" in
+        a) cmd="add" ;;
+        g) cmd="go" ;;
+        ls) cmd="list" ;;
+        browse|fz) cmd="ui" ;;
+        rm|del) cmd="remove" ;;
+        mv) cmd="rename" ;;
+        exp) cmd="export" ;;
+        imp) cmd="import" ;;
+        e) cmd="edit" ;;
+        check) cmd="validate" ;;
+        r) cmd="recent" ;;
+        h) cmd="help" ;;
+    esac
+
+    # Command-specific completion
+    case "$cmd" in
+        go|remove)
+            local bookmarks=$(_bmc_get_bookmarks)
+            COMPREPLY=( $(compgen -W "$bookmarks" -- "$cur") )
+            ;;
+        rename)
+            if [ $COMP_CWORD -eq 2 ]; then
+                local bookmarks=$(_bmc_get_bookmarks)
+                COMPREPLY=( $(compgen -W "$bookmarks" -- "$cur") )
+            fi
+            ;;
+        add)
+            case "$prev" in
+                -d|--description|-t|--tags)
+                    COMPREPLY=()
+                    ;;
+                *)
+                    COMPREPLY=( $(compgen -d -- "$cur") )
+                    ;;
+            esac
+            ;;
+        list)
+            if [[ "$cur" == -* ]]; then
+                COMPREPLY=( $(compgen -W "--tag" -- "$cur") )
+            elif [[ "$prev" == "--tag" ]]; then
+                local tags=$(_bmc_get_tags)
+                COMPREPLY=( $(compgen -W "$tags" -- "$cur") )
+            fi
+            ;;
+        clean)
+            [[ "$cur" == -* ]] && COMPREPLY=( $(compgen -W "--dry-run" -- "$cur") )
+            ;;
+        import|export)
+            COMPREPLY=( $(compgen -f -- "$cur") )
+            ;;
+    esac
+
+    return 0
+}
+
+# Get bookmark names
+_bmc_get_bookmarks() {
+    local bmc_cmd="bmc"
+
+    command -v "$bmc_cmd" >/dev/null 2>&1 || return 1
+
+    NO_COLOR=1 "$bmc_cmd" list 2>/dev/null | \
+        awk 'NR > 2 && NF > 0 && $1 != "Tags:" { print $1 }' || true
+}
+
+# Get tags
+_bmc_get_tags() {
+    local bmc_cmd="bmc"
+
+    command -v "$bmc_cmd" >/dev/null 2>&1 || return 1
+
+    NO_COLOR=1 "$bmc_cmd" tags 2>/dev/null | \
+        awk 'NF > 0 && $1 != "All" && $1 != "No" { print $1 }' || true
+}
+
+complete -F _bmc_completions bmc
+command -v bm >/dev/null 2>&1 && complete -F _bmc_completions bm
diff --git a/completions/bmc.fish b/completions/bmc.fish
new file mode 100644
index 0000000..713a853
--- /dev/null
+++ b/completions/bmc.fish
@@ -0,0 +1,87 @@
+# Fish completion for bmc (bookmark-cli)
+
+function __fish_bmc_needs_command
+    set -l cmd (commandline -opc)
+    test (count $cmd) -eq 1
+end
+
+function __fish_bmc_using_command
+    set -l cmd (commandline -opc)
+    if test (count $cmd) -gt 1
+        test $argv[1] = $cmd[2]
+    else
+        return 1
+    end
+end
+
+function __fish_bmc_bookmarks
+    command -v bmc >/dev/null 2>&1 || return 1
+
+    NO_COLOR=1 bmc list 2>/dev/null | \
+        awk 'NR > 2 && NF > 0 && $1 != "Tags:" { print $1 }'
+end
+
+function __fish_bmc_tags
+    command -v bmc >/dev/null 2>&1 || return 1
+
+    NO_COLOR=1 bmc tags 2>/dev/null | \
+        awk 'NF > 0 && $1 != "All" && $1 != "No" { print $1 }'
+end
+
+# Subcommands
+complete -c bmc -f -n __fish_bmc_needs_command -a add -d 'Add a bookmark'
+complete -c bmc -f -n __fish_bmc_needs_command -a a -d 'Alias for add'
+complete -c bmc -f -n __fish_bmc_needs_command -a go -d 'Navigate to bookmark'
+complete -c bmc -f -n __fish_bmc_needs_command -a g -d 'Alias for go'
+complete -c bmc -f -n __fish_bmc_needs_command -a list -d 'List bookmarks'
+complete -c bmc -f -n __fish_bmc_needs_command -a ls -d 'Alias for list'
+complete -c bmc -f -n __fish_bmc_needs_command -a tags -d 'Show all tags'
+complete -c bmc -f -n __fish_bmc_needs_command -a ui -d 'Interactive UI'
+complete -c bmc -f -n __fish_bmc_needs_command -a browse -d 'Alias for ui'
+complete -c bmc -f -n __fish_bmc_needs_command -a fz -d 'Alias for ui'
+complete -c bmc -f -n __fish_bmc_needs_command -a remove -d 'Remove bookmark'
+complete -c bmc -f -n __fish_bmc_needs_command -a rm -d 'Alias for remove'
+complete -c bmc -f -n __fish_bmc_needs_command -a del -d 'Alias for remove'
+complete -c bmc -f -n __fish_bmc_needs_command -a rename -d 'Rename bookmark'
+complete -c bmc -f -n __fish_bmc_needs_command -a mv -d 'Alias for rename'
+complete -c bmc -f -n __fish_bmc_needs_command -a export -d 'Export bookmarks'
+complete -c bmc -f -n __fish_bmc_needs_command -a exp -d 'Alias for export'
+complete -c bmc -f -n __fish_bmc_needs_command -a import -d 'Import bookmarks'
+complete -c bmc -f -n __fish_bmc_needs_command -a imp -d 'Alias for import'
+complete -c bmc -f -n __fish_bmc_needs_command -a edit -d 'Edit bookmark file'
+complete -c bmc -f -n __fish_bmc_needs_command -a e -d 'Alias for edit'
+complete -c bmc -f -n __fish_bmc_needs_command -a validate -d 'Validate bookmarks'
+complete -c bmc -f -n __fish_bmc_needs_command -a check -d 'Alias for validate'
+complete -c bmc -f -n __fish_bmc_needs_command -a clean -d 'Remove invalid bookmarks'
+complete -c bmc -f -n __fish_bmc_needs_command -a doctor -d 'Health diagnostic'
+complete -c bmc -f -n __fish_bmc_needs_command -a recent -d 'Recent bookmarks'
+complete -c bmc -f -n __fish_bmc_needs_command -a r -d 'Alias for recent'
+complete -c bmc -f -n __fish_bmc_needs_command -a frequent -d 'Frequent bookmarks'
+complete -c bmc -f -n __fish_bmc_needs_command -a stats -d 'Usage statistics'
+complete -c bmc -f -n __fish_bmc_needs_command -a help -d 'Show help'
+complete -c bmc -f -n __fish_bmc_needs_command -a h -d 'Alias for help'
+
+# Bookmark name completion
+complete -c bmc -f -n '__fish_bmc_using_command go' -a '(__fish_bmc_bookmarks)'
+complete -c bmc -f -n '__fish_bmc_using_command g' -a '(__fish_bmc_bookmarks)'
+complete -c bmc -f -n '__fish_bmc_using_command remove' -a '(__fish_bmc_bookmarks)'
+complete -c bmc -f -n '__fish_bmc_using_command rm' -a '(__fish_bmc_bookmarks)'
+complete -c bmc -f -n '__fish_bmc_using_command del' -a '(__fish_bmc_bookmarks)'
+complete -c bmc -f -n '__fish_bmc_using_command rename' -a '(__fish_bmc_bookmarks)'
+complete -c bmc -f -n '__fish_bmc_using_command mv' -a '(__fish_bmc_bookmarks)'
+
+# Options for add command
+complete -c bmc -f -n '__fish_bmc_using_command add' -s d -l description -d 'Bookmark description'
+complete -c bmc -f -n '__fish_bmc_using_command add' -s t -l tags -d 'Tags (comma-separated)'
+complete -c bmc -f -n '__fish_bmc_using_command a' -s d -l description -d 'Bookmark description'
+complete -c bmc -f -n '__fish_bmc_using_command a' -s t -l tags -d 'Tags (comma-separated)'
+
+# Options for list command
+complete -c bmc -f -n '__fish_bmc_using_command list' -l tag -d 'Filter by tag' -a '(__fish_bmc_tags)'
+complete -c bmc -f -n '__fish_bmc_using_command ls' -l tag -d 'Filter by tag' -a '(__fish_bmc_tags)'
+
+# Options for clean command
+complete -c bmc -f -n '__fish_bmc_using_command clean' -l dry-run -d 'Preview without removing'
+
+# Alias support
+complete -c bm -w bmc
diff --git a/tests/test_completion.bats b/tests/test_completion.bats
new file mode 100644
index 0000000..10ea5c9
--- /dev/null
+++ b/tests/test_completion.bats
@@ -0,0 +1,108 @@
+#!/usr/bin/env bats
+
+setup() {
+    export TEST_DIR=$(mktemp -d)
+    export BM_FILE="$TEST_DIR/bookmarks"
+    export BM_HISTORY="$TEST_DIR/history"
+
+    # Create test bookmarks
+    mkdir -p "$TEST_DIR/projects"
+    echo "project1:$TEST_DIR/projects/proj1:Test project 1:work,dev" > "$BM_FILE"
+    echo "project2:$TEST_DIR/projects/proj2:Test project 2:personal" >> "$BM_FILE"
+    echo "sample-project:$TEST_DIR/projects/sample:Sample:test" >> "$BM_FILE"
+
+    export PATH="$BATS_TEST_DIRNAME/../cli:$PATH"
+}
+
+teardown() {
+    rm -rf "$TEST_DIR"
+}
+
+@test "completion: bmc list outputs parseable bookmark names" {
+    run bmc list
+    [ "$status" -eq 0 ]
+    [[ "$output" =~ "project1" ]]
+    [[ "$output" =~ "project2" ]]
+    [[ "$output" =~ "sample-project" ]]
+}
+
+@test "completion: bmc list with NO_COLOR produces clean output" {
+    NO_COLOR=1 run bmc list
+    [ "$status" -eq 0 ]
+    [[ ! "$output" =~ $'\033' ]]
+}
+
+@test "completion: bookmark names can be extracted from list output" {
+    local names=$(NO_COLOR=1 bmc list | awk 'NR > 2 && NF > 0 && $1 != "Tags:" { print $1 }')
+
+    [ $(echo "$names" | wc -l | tr -d ' ') -eq 3 ]
+    echo "$names" | grep -q "^project1$"
+    echo "$names" | grep -q "^project2$"
+    echo "$names" | grep -q "^sample-project$"
+}
+
+@test "completion: tags can be extracted from tags output" {
+    run bmc tags
+    [ "$status" -eq 0 ]
+    [[ "$output" =~ "work" ]]
+    [[ "$output" =~ "personal" ]]
+    [[ "$output" =~ "dev" ]]
+    [[ "$output" =~ "test" ]]
+}
+
+@test "completion: empty bookmark file handled gracefully" {
+    > "$BM_FILE"
+    run bmc list
+    [ "$status" -eq 0 ]
+    [[ "$output" =~ "No bookmarks found" ]]
+}
+
+@test "completion: bash completion script has valid syntax" {
+    [ -f "$BATS_TEST_DIRNAME/../completions/bmc.bash" ]
+    bash -n "$BATS_TEST_DIRNAME/../completions/bmc.bash"
+}
+
+@test "completion: zsh completion script exists" {
+    [ -f "$BATS_TEST_DIRNAME/../completions/_bmc" ]
+}
+
+@test "completion: fish completion script exists" {
+    [ -f "$BATS_TEST_DIRNAME/../completions/bmc.fish" ]
+}
+
+@test "completion: bookmark names with hyphens and underscores" {
+    echo "my-project:$TEST_DIR:Test:work" >> "$BM_FILE"
+    echo "my_project:$TEST_DIR:Test:work" >> "$BM_FILE"
+
+    local names=$(NO_COLOR=1 bmc list | awk 'NR > 2 && NF > 0 && $1 != "Tags:" { print $1 }')
+    echo "$names" | grep -q "my-project"
+    echo "$names" | grep -q "my_project"
+}
+
+@test "completion: bmc list completes quickly with many bookmarks" {
+    for i in {1..50}; do
+        echo "test$i:$TEST_DIR:Test $i:test" >> "$BM_FILE"
+    done
+
+    local start=$(date +%s)
+    run bmc list
+    local end=$(date +%s)
+    local duration=$((end - start))
+
+    [ "$status" -eq 0 ]
+    [ "$duration" -lt 2 ]
+}
+
+@test "completion: bash completion can be sourced" {
+    bash -c "source $BATS_TEST_DIRNAME/../completions/bmc.bash && declare -F _bmc_completions"
+}
+
+@test "completion: bash helper functions work" {
+    bash -c "
+        source $BATS_TEST_DIRNAME/../completions/bmc.bash
+        export BM_FILE='$BM_FILE'
+        export PATH='$BATS_TEST_DIRNAME/../cli:\$PATH'
+        bookmarks=\$(_bmc_get_bookmarks)
+        echo \"\$bookmarks\" | grep -q 'project1'
+    "
+}