Option 1 - Using Homebrew

This is the easiest way and will provide automatic updates.

  1. Install homebrew

    ruby -e "$(curl -fsSL https://raw.githubusercontent.com/Homebrew/install/master/install)"

  2. Install adb 

    brew install android-platform-tools

  3. Start using adb

    adb devices

 

Option 2 - Manually

  1. Delete your old installation (optional)

    rm -rf ~/.android-sdk-macosx/

  2. Download the Mac SDK Tools from the Android developer site under "SDK Tools Only"

  3. Go to your Downloads folder

    cd ~/Downloads/

  4. Unzip the tools you downloaded

    unzip android-sdk*.zip

  5. Move them somewhere you won't accidentally delete them

    mv android-sdk-macosx/ ~/.android-sdk-macosx

  6. Run the SDK Manager

    sh ~/.android-sdk-macosx/tools/android

  7. Uncheck everything but Android SDK Platform-tools (optional)

  8. Click Install Packages, accept licenses, click Install. Close the SDK Manager window.

  9. Add platform-tools to your path

    echo 'export PATH=$PATH:~/.android-sdk-macosx/platform-tools/' >> ~/.bash_profile

  10. Refresh your bash profile (or restart your terminal app)

    source ~/.bash_profile

  11. Start using adb

    adb devices

from :http://stackoverflow.com/questions/31374085/installing-adb-on-mac-os-x