The Old Windmill is a heritage-listed tower mill in Observatory Park adjacent to Wickham Park at 226 Wickham Terrace, Spring Hill, City of Brisbane, Queensland, Australia. It was built in the 1820s by convict labour in the Moreton Bay penal settlement and is the oldest surviving building in Queensland. It is also known as Brisbane Observatory and Windmill Tower. It was added to the Queensland Heritage Register on 21 October 1992. Today it is the centrepiece of Observatory Park and a lookout over parts of the Brisbane CBD.

Wickham Terrace is one of the historic streets of Brisbane, Queensland, Australia. It is known as the street of private medical specialists.