Abstract: A wheelchair braking device (10) adapted to automatically engage when the wheelchair (12) to which the device (10) is mounted is unoccupied. The braking device (10) includes a support structure (28) to which is pivotably mounted a sensing lever (14) and a braking lever (22). A biasing element (30) is coupled to the braking lever (22) to bias the braking lever (22) in a first rotational direction relative to the support structure (28) and into engagement with a wheel (32) of the wheelchair (12). The sensing and braking levers (14, 22) are interconnected such that the biasing element (30) operates through the braking lever (22) to bias the sensing lever (14) in a second rotational direction relative to the support structure (28), corresponding to a brake engagement position for the sensing lever (14).