Lilia Osterloh (born April 7, 1978 in Columbus, Ohio) is a retired tennis player from the United States, who started a professional career in August 1997. She reached her highest singles ranking on the WTA Tour on April 23, 2001, when she became world no. 41. Her career-high doubles ranking on the WTA tour is no. 77, which she reached on August 23, 1999.