AimTo assess the effectiveness of decision aids for genetic counsellees to improve their conflicts in decision‐making and psychological well‐being when considering genetic tests for inherited genetic diseases, and their knowledge about these tests and their genetic risks.DesignSystematic review.Data sourcesSix electronic databases (PubMed, MEDLINE, OVID Nursing, APA PsycINFO, EMBASE and CINAHL) were searched from inception to May 2022.Review methodsOnly randomised controlled trials that examined the effect of decision aids for information provision centring genetic testing on outcomes including decisional conflicts, informed choice making, knowledge on genetic risks or genetic tests, and psychological outcomes among participants who had undergone genetic counselling were included. Their risk of bias was assessed using the Version 2 of the Cochrane risk of bias tool for randomised trials. Results were presented narratively. The review was conducted according to the PRISMA checklist.ResultsEight included studies examined the effect of booklet‐based, computer‐based, film‐based or web‐based decision aids on individuals considering genetic testing for their increased cancer risks. Despite contrasting findings across studies, they showed that decision aids enable genetic counsellees to feel more informed in decision‐making on genetic tests, although most showed no effect on decisional conflict. Knowledge of genetic counsellees on genetic risks and genetic tests were increased after the use of decision aids. Most studies showed no significant effect on any psychological outcomes assessed.ConclusionsReview findings corroborate the use of decision aids to enhance the effective delivery of genetic counselling, enabling genetic counsellees to gain more knowledge of genetic tests and feel more informed in making decisions to have these tests.Relevance to clinical practiceDecision aids can be used to support nurse‐led genetic counselling for better knowledge acquisition and decision‐making among counsellees.No patient or public contributionPatient or public contribution is not applicable as this is a systematic review.