The Sedili Besar River (Malay: Sungai Sedili Besar) is a river in Kota Tinggi District, Johor, Malaysia.

At the southern end of Teluk Mahkota bay is a smaller river known as Sungai Sedili Kechil.

The word kechil means small in Malay language.

The river mouth is situated at the northern end of Teluk Mahkota bay, and empties into the South China Sea.

The river has a total drainage basin area of 271 km2.