The Aboriginal Witnesses Act was a series ordinances and amendments enacted by lieutenant Governor George Grey, Governor of South Australia during the early colonial period of South Australia. The act was established "To facilitate the admission of the unsworn testimony of Aboriginal inhabitants of South Australia and parts adjacent".
Despite the act's stated aims being to facilitate Aboriginal testimony, it had the opposite effect, creating a situation where the massacre of Aboriginal peoples by European colonisers could not be tried solely on the evidence of Aboriginal witnesses.