Lilian Kasait Rengeruk (born 3 May 1997) is a Kenyan female long-distance runner. She won the bronze medal in the women's senior race at the 2017 World Cross Country Championships. Rengeruk is the former 3000 metres World Under-18 champion and World U20 Championship silver medallist. In September 2022, Rengeruk was banned for 10 months commencing April of that year due to the use of hormone therapy drug.