Sydenham developed after the Illawarra railway line came through the area to Hurstville in the late 1800s. It was named after Sydenham, a suburb of London, similar for its close proximity to the city and a railway junction. The station was originally known as Marrickville when it opened on 15 October 1884. It was changed to Sydenham on 19 March 1895 when a new line was being built to Bankstown and the first station was to be called Marrickville. The post office opened in April 1899 as Tempe Park and was only renamed Sydenham in 1964.