diff --git a/CHANGELOG.md b/CHANGELOG.md
index 1df7848..7fc2d02 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -6,6 +6,7 @@
 - Fix N+1 queries in `blame`, `stale`, `stats`, and `log` commands
 - Configuration via git config: `pkgs.ecosystems`, `pkgs.ignoredDirs`, `pkgs.ignoredFiles`
 - `git pkgs info --ecosystems` to show available ecosystems and their status
+- `git pkgs completions` command for bash/zsh tab completion
 - `-q, --quiet` flag to suppress informational messages
 - `git pkgs diff` now supports `commit..commit` range syntax
 - `--git-dir` and `--work-tree` global options (also respects `GIT_WORK_TREE` env var)
diff --git a/README.md b/README.md
index e70421c..9b6f8ee 100644
--- a/README.md
+++ b/README.md
@@ -371,6 +371,21 @@ diff --git a/Gemfile.lock b/Gemfile.lock
 
 Use `git diff --no-textconv` to see the raw lockfile diff. To remove: `git pkgs diff-driver --uninstall`
 
+### Shell completions
+
+Enable tab completion for commands:
+
+```bash
+# Bash: add to ~/.bashrc
+eval "$(git pkgs completions bash)"
+
+# Zsh: add to ~/.zshrc
+eval "$(git pkgs completions zsh)"
+
+# Or auto-install to standard completion directories
+git pkgs completions install
+```
+
 ## Configuration
 
 git-pkgs respects [standard git configuration](https://git-scm.com/docs/git-config).
diff --git a/lib/git/pkgs.rb b/lib/git/pkgs.rb
index b6127d5..c0943a5 100644
--- a/lib/git/pkgs.rb
+++ b/lib/git/pkgs.rb
@@ -36,6 +36,7 @@
 require_relative "pkgs/commands/upgrade"
 require_relative "pkgs/commands/schema"
 require_relative "pkgs/commands/diff_driver"
+require_relative "pkgs/commands/completions"
 
 module Git
   module Pkgs
diff --git a/lib/git/pkgs/cli.rb b/lib/git/pkgs/cli.rb
index dbac189..2453ae2 100644
--- a/lib/git/pkgs/cli.rb
+++ b/lib/git/pkgs/cli.rb
@@ -14,7 +14,8 @@ class CLI
           "info" => "Show database size and row counts",
           "branch" => "Manage tracked branches",
           "schema" => "Show database schema",
-          "diff-driver" => "Install git textconv driver for lockfile diffs"
+          "diff-driver" => "Install git textconv driver for lockfile diffs",
+          "completions" => "Generate shell completions"
         },
         "Query" => {
           "list" => "List dependencies at a commit",
diff --git a/lib/git/pkgs/commands/completions.rb b/lib/git/pkgs/commands/completions.rb
new file mode 100644
index 0000000..e511e3b
--- /dev/null
+++ b/lib/git/pkgs/commands/completions.rb
@@ -0,0 +1,234 @@
+# frozen_string_literal: true
+
+module Git
+  module Pkgs
+    module Commands
+      class Completions
+        COMMANDS = CLI::COMMANDS
+        SUBCOMMAND_OPTIONS = {
+          "hooks" => %w[--install --uninstall],
+          "branch" => %w[--add --remove --list],
+          "diff" => %w[--format],
+          "list" => %w[--format --type],
+          "tree" => %w[--format],
+          "history" => %w[--format --limit],
+          "search" => %w[--format --limit],
+          "blame" => %w[--format],
+          "stale" => %w[--days --format],
+          "stats" => %w[--format],
+          "log" => %w[--limit --format],
+          "show" => %w[--format],
+          "where" => %w[--format],
+          "why" => %w[--format]
+        }.freeze
+
+        BASH_SCRIPT = <<~'BASH'
+          _git_pkgs() {
+            local cur prev commands
+            COMPREPLY=()
+            cur="${COMP_WORDS[COMP_CWORD]}"
+            prev="${COMP_WORDS[COMP_CWORD-1]}"
+
+            commands="init update hooks info list tree history search where why blame stale stats diff branch show log upgrade schema completions"
+
+            if [[ ${COMP_CWORD} -eq 2 && ${COMP_WORDS[1]} == "pkgs" ]]; then
+              COMPREPLY=( $(compgen -W "${commands}" -- ${cur}) )
+              return 0
+            fi
+
+            if [[ ${COMP_CWORD} -eq 1 ]]; then
+              COMPREPLY=( $(compgen -W "${commands}" -- ${cur}) )
+              return 0
+            fi
+
+            case "${prev}" in
+              hooks)
+                COMPREPLY=( $(compgen -W "--install --uninstall --help" -- ${cur}) )
+                ;;
+              branch)
+                COMPREPLY=( $(compgen -W "--add --remove --list --help" -- ${cur}) )
+                ;;
+              completions)
+                COMPREPLY=( $(compgen -W "bash zsh install --help" -- ${cur}) )
+                ;;
+              diff|list|tree|history|search|blame|stale|stats|log|show|where|why)
+                COMPREPLY=( $(compgen -W "--format --help" -- ${cur}) )
+                ;;
+            esac
+
+            return 0
+          }
+
+          # Support both 'git pkgs' and 'git-pkgs' invocations
+          complete -F _git_pkgs git-pkgs
+
+          # For 'git pkgs' subcommand completion
+          if declare -F _git >/dev/null 2>&1; then
+            _git_pkgs_git_wrapper() {
+              if [[ ${COMP_WORDS[1]} == "pkgs" ]]; then
+                _git_pkgs
+              fi
+            }
+          fi
+        BASH
+
+        ZSH_SCRIPT = <<~'ZSH'
+          #compdef git-pkgs
+
+          _git-pkgs() {
+            local -a commands
+            commands=(
+              'init:Initialize the package database'
+              'update:Update the database with new commits'
+              'hooks:Manage git hooks for auto-updating'
+              'info:Show database size and row counts'
+              'branch:Manage tracked branches'
+              'list:List dependencies at a commit'
+              'tree:Show dependency tree grouped by type'
+              'history:Show the history of a package'
+              'search:Find a dependency across all history'
+              'where:Show where a package appears in manifest files'
+              'why:Explain why a dependency exists'
+              'blame:Show who added each dependency'
+              'stale:Show dependencies that have not been updated'
+              'stats:Show dependency statistics'
+              'diff:Show dependency changes between commits'
+              'show:Show dependency changes in a commit'
+              'log:List commits with dependency changes'
+              'upgrade:Upgrade database after git-pkgs update'
+              'schema:Show database schema'
+              'completions:Generate shell completions'
+            )
+
+            _arguments -C \
+              '1: :->command' \
+              '*:: :->args'
+
+            case $state in
+              command)
+                _describe -t commands 'git-pkgs commands' commands
+                ;;
+              args)
+                case $words[1] in
+                  hooks)
+                    _arguments \
+                      '--install[Install git hooks]' \
+                      '--uninstall[Remove git hooks]' \
+                      '--help[Show help]'
+                    ;;
+                  branch)
+                    _arguments \
+                      '--add[Add a branch to track]' \
+                      '--remove[Remove a tracked branch]' \
+                      '--list[List tracked branches]' \
+                      '--help[Show help]'
+                    ;;
+                  completions)
+                    _arguments '1:shell:(bash zsh install)'
+                    ;;
+                  diff|list|tree|history|search|blame|stale|stats|log|show|where|why)
+                    _arguments \
+                      '--format[Output format]:format:(table json csv)' \
+                      '--help[Show help]'
+                    ;;
+                esac
+                ;;
+            esac
+          }
+
+          _git-pkgs "$@"
+        ZSH
+
+        def initialize(args)
+          @args = args
+        end
+
+        def run
+          shell = @args.first
+
+          case shell
+          when "bash"
+            puts BASH_SCRIPT
+          when "zsh"
+            puts ZSH_SCRIPT
+          when "install"
+            install_completions
+          when "-h", "--help", nil
+            print_help
+          else
+            $stderr.puts "Unknown shell: #{shell}"
+            $stderr.puts "Supported: bash, zsh, install"
+            exit 1
+          end
+        end
+
+        def install_completions
+          shell = detect_shell
+
+          case shell
+          when "zsh"
+            install_zsh_completions
+          when "bash"
+            install_bash_completions
+          else
+            $stderr.puts "Could not detect shell. Please run one of:"
+            $stderr.puts "  eval \"$(git pkgs completions bash)\""
+            $stderr.puts "  eval \"$(git pkgs completions zsh)\""
+            exit 1
+          end
+        end
+
+        def detect_shell
+          shell_env = ENV["SHELL"] || ""
+          if shell_env.include?("zsh")
+            "zsh"
+          elsif shell_env.include?("bash")
+            "bash"
+          end
+        end
+
+        def install_bash_completions
+          dir = File.expand_path("~/.local/share/bash-completion/completions")
+          FileUtils.mkdir_p(dir)
+          path = File.join(dir, "git-pkgs")
+          File.write(path, BASH_SCRIPT)
+          puts "Installed bash completions to #{path}"
+          puts "Restart your shell or run: source #{path}"
+        end
+
+        def install_zsh_completions
+          dir = File.expand_path("~/.zsh/completions")
+          FileUtils.mkdir_p(dir)
+          path = File.join(dir, "_git-pkgs")
+          File.write(path, ZSH_SCRIPT)
+          puts "Installed zsh completions to #{path}"
+          puts ""
+          puts "Add to your ~/.zshrc if not already present:"
+          puts "  fpath=(~/.zsh/completions $fpath)"
+          puts "  autoload -Uz compinit && compinit"
+          puts ""
+          puts "Then restart your shell or run: source ~/.zshrc"
+        end
+
+        def print_help
+          puts <<~HELP
+            Usage: git pkgs completions <shell>
+
+            Generate shell completion scripts.
+
+            Shells:
+              bash      Output bash completion script
+              zsh       Output zsh completion script
+              install   Auto-install completions for your shell
+
+            Examples:
+              git pkgs completions bash > ~/.local/share/bash-completion/completions/git-pkgs
+              git pkgs completions zsh > ~/.zsh/completions/_git-pkgs
+              eval "$(git pkgs completions bash)"
+              git pkgs completions install
+          HELP
+        end
+      end
+    end
+  end
+end
diff --git a/test/git/pkgs/test_completions.rb b/test/git/pkgs/test_completions.rb
new file mode 100644
index 0000000..96f7ac1
--- /dev/null
+++ b/test/git/pkgs/test_completions.rb
@@ -0,0 +1,133 @@
+# frozen_string_literal: true
+
+require "test_helper"
+require "stringio"
+require "tmpdir"
+
+class Git::Pkgs::TestCompletionsCommand < Minitest::Test
+  def test_bash_output
+    output = capture_stdout do
+      Git::Pkgs::Commands::Completions.new(["bash"]).run
+    end
+
+    assert_includes output, "_git_pkgs()"
+    assert_includes output, "COMPREPLY"
+    assert_includes output, "compgen"
+    assert_includes output, "complete -F _git_pkgs git-pkgs"
+  end
+
+  def test_zsh_output
+    output = capture_stdout do
+      Git::Pkgs::Commands::Completions.new(["zsh"]).run
+    end
+
+    assert_includes output, "#compdef git-pkgs"
+    assert_includes output, "_git-pkgs()"
+    assert_includes output, "_describe"
+    assert_includes output, "_arguments"
+  end
+
+  def test_help_output
+    output = capture_stdout do
+      Git::Pkgs::Commands::Completions.new(["--help"]).run
+    end
+
+    assert_includes output, "Usage: git pkgs completions"
+    assert_includes output, "bash"
+    assert_includes output, "zsh"
+    assert_includes output, "install"
+  end
+
+  def test_no_args_shows_help
+    output = capture_stdout do
+      Git::Pkgs::Commands::Completions.new([]).run
+    end
+
+    assert_includes output, "Usage: git pkgs completions"
+  end
+
+  def test_unknown_shell_exits_with_error
+    assert_raises(SystemExit) do
+      capture_stderr do
+        Git::Pkgs::Commands::Completions.new(["fish"]).run
+      end
+    end
+  end
+
+  def test_bash_includes_all_commands
+    output = capture_stdout do
+      Git::Pkgs::Commands::Completions.new(["bash"]).run
+    end
+
+    # Check that main commands are included
+    assert_includes output, "init"
+    assert_includes output, "update"
+    assert_includes output, "history"
+    assert_includes output, "completions"
+  end
+
+  def test_zsh_includes_all_commands
+    output = capture_stdout do
+      Git::Pkgs::Commands::Completions.new(["zsh"]).run
+    end
+
+    assert_includes output, "'init:Initialize the package database'"
+    assert_includes output, "'completions:Generate shell completions'"
+  end
+
+  def test_install_creates_bash_completions
+    Dir.mktmpdir do |tmpdir|
+      ENV["HOME"] = tmpdir
+      ENV["SHELL"] = "/bin/bash"
+
+      output = capture_stdout do
+        Git::Pkgs::Commands::Completions.new(["install"]).run
+      end
+
+      completion_file = File.join(tmpdir, ".local/share/bash-completion/completions/git-pkgs")
+      assert File.exist?(completion_file), "Completion file should exist"
+      assert_includes File.read(completion_file), "_git_pkgs()"
+      assert_includes output, "Installed bash completions"
+    end
+  ensure
+    ENV["HOME"] = Dir.home
+    ENV.delete("SHELL")
+  end
+
+  def test_install_creates_zsh_completions
+    Dir.mktmpdir do |tmpdir|
+      ENV["HOME"] = tmpdir
+      ENV["SHELL"] = "/bin/zsh"
+
+      output = capture_stdout do
+        Git::Pkgs::Commands::Completions.new(["install"]).run
+      end
+
+      completion_file = File.join(tmpdir, ".zsh/completions/_git-pkgs")
+      assert File.exist?(completion_file), "Completion file should exist"
+      assert_includes File.read(completion_file), "#compdef git-pkgs"
+      assert_includes output, "Installed zsh completions"
+    end
+  ensure
+    ENV["HOME"] = Dir.home
+    ENV.delete("SHELL")
+  end
+
+  def capture_stdout
+    original = $stdout
+    $stdout = StringIO.new
+    yield
+    $stdout.string
+  ensure
+    $stdout = original
+  end
+
+  def capture_stderr
+    original = $stderr
+    $stderr = StringIO.new
+    yield
+    $stderr.string
+  ensure
+    $stderr = original
+  end
+end