In the next general election in 2009, Tsotetsi was elected to an ANC seat in the National Assembly, the lower parliamentary house, where she continued to serve the Gauteng constituency. She served two terms in the seat, gaining re-election in the 2014 general election, and during her second term she served as a party whip in the Portfolio Committee on Telecommunications and Postal Services. In the 2019 general election, she was demoted on the ANC's party list and, ranked 43 on the regional list for Gauteng, she failed to gain re-election.
