The Rondevlei Nature Reserve is located in Grassy Park, Zeekoevlei and Lavenderhill, suburbs of Cape Town, South Africa.

The bird sanctuary covers approximately 290 hectares (720 acres) of mostly permanent wetland and consists of a single large brackish lagoon.

Rondevlei is home to about 230 bird species, a variety of small mammals and reptiles like caracal, porcupine, Cape fox, grysbuck, steenbuck and mongoose, as well as a hippopotamus population which was re-introduced in 1981 as a means to control an alien grass species from South America, which had covered the shoreline and was threatening to engulf the vlei itself.

In February 2004, a young hippo calf named Hugo or Houdini escaped from Rondevlei after it was bullied by an older dominant male and was on the run for 10 months until it was caught in December and moved to an Eastern Cape private reserve.

To prevent flooding of the built-up areas, which contained then mainly sub-economic housing, a dam at the south-eastern end of the vlei was built to permanently lower the level of Rondevlei.