Dato' Onn Hafiz bin Dato' Ghazi is a Malaysian politician who has served as the 19th Menteri Besar of Johor and Member of the Johor State Legislative Assembly (MLA) for Machap since March 2022. He previously served as MLA for Layang-Layang from May 2018 to March 2022. From March 2020 to his promotion to Menteri Besarship in March 2022, he served as Member of the Johor State Executive Council (EXCO) in the Barisan Nasional (BN) state administration under former Menteri Besar Hasni Mohammad. He is a member of the United Malays National Organisation (UMNO), a component party of the BN coalition. He has also served as the State Chairman of BN and UMNO of Johor since February 2024 and December 2023 respectively.

The Menteri Besar of Johor or Chief Minister of Johor is the head of government in the Malaysian state of Johor. According to convention, the Menteri Besar is the leader of the majority party or largest coalition party of the Johor State Legislative Assembly.