Nyamtaishiryn Nomtoibayar (; born 2 July 1978) is a Mongolian politician. He was elected as a member of the State Great Khural in 2012, 2016, and then again in 2024. He also served as Minister of Labour and Social Protection from 2016 to 2017.
Nomtoibayar was a member of the Mongolian People's Party (MPP). He was first elected as a member of parliament in the 2012 parliamentary election, and later was re-elected in the 2016 parliamentary election. He was appointed Minister of Labour and Social Protection for the cabinet of Jargaltulgyn Erdenebat on 8 July 2016. He served as Labour Minister until September 2017, when Prime Minister Erdenebat resigned after losing a motion of no confidence.
Nomtoibayar was re-elected to the State Great Khural in the 2016 parliamentary election, where the MPP won a supermajority. However, his disagreements with other MPP members and unparliamentary behavior would lead to his expulsion from the ruling party in January 2020. He unsuccessfully ran as an independent in the 2020 parliamentary election.
On 9 July 2020, when legal proceedings for several former ministers and politicians began, he was arrested and sentenced to 5 years and 5 months in prison after being found guilty of abusing power as Labour Minister back in 2017. He was released from prison on 1 April 2021, after serving a total of nine months.
For his bid in the 2024 elections, Nomtoibayar formed the National Coalition with the Mongolian Green Party and the Mongolian National Democratic Party on 19 January 2024. The coalition won 4 out of 126 seats in the 2024 parliamentary elections. As of October 2025, he serves as an opposition member of the State Great Khural and leader of the National Coalition.