Kota Tinggi District is a district in the Malaysian state of Johor. It is the largest district in the state with an area of 3,488.7 square kilometres (1,347.0 sq mi). The population was 187,824 in 2010. The principal town is Kota Tinggi.

Johor, is a state of Malaysia in the south of the Malay Peninsula. It shares borders with Pahang, Malacca and Negeri Sembilan to the north. Johor shares maritime borders with Singapore to the south and Indonesia to both the west and east. As of 2023, the state's population is 4.19 million, making it the second most populous state in Malaysia, after Selangor. Johor Bahru is the capital city and the economic centre of the state, Kota Iskandar is the state administrative centre and Muar serves as the royal capital.