Ansar may refer to:
- Ansar, Lebanon, a village in south Lebanon
- Ansar, North Khorasan, a village in North Khorasan Province, Iran
- Ansar, a village in Siwan district of Bihar, India
- Ansar (deity), an ancient Babylonian sky god
- Ansar (Islam), citizens from Medina who helped Mohammed
- Ansar (military), a class of Arabian warriors
- Ansar (Sudan), a Sufi religious movement in the Sudan
- Al Ansar / Al-Ansar
- Al-Ansar FC, a Lebanese football team
- Al Ansaar (Libya), a Libyan football team
- Al-Ansar (Saudi Arabia), a Saudi Arabian multi-sports club
- Al-Ansar (Saudi Arabia, basketball)
- Others
- Ansar Bahini, an internal security force in Bangladesh.
- Ansar al-Islam, a Sunni Islamist group of Iraqis promoting a radical interpretation of Islam
- Ansar-e Hezbollah, a militant conservative Islamic group in Iran
- Ansar al-Sharia, a number of Islamist groups active in the Arab world
- Ansar Dine, a Tuareg Islamist group, accused of having links with Al-Qaeda in the Islamic Maghreb and other Islamist groups
- Ansarullah, an auxiliary organization of the Ahmadiyya Muslim Community
- Ansaaru Allah Community, a black nationalist group founded by Malachi Z. York