Ounissi was elected to the Assembly of the Representatives of the People on 26 October 2014 as a member of the Ennahdha representing the constituency of France Nord, an overseas constituency for members of the Tunisian diaspora in France. She was the youngest Ennahda candidate and became one of the youngest members of parliament. She sat on the Committees of Finance, Planning and Development and of Martyrs and Wounded of the Revolution. During the Bardo National Museum attack on 18 March 2015, she was tweeting live updates detailing the panic and evacuation.