Presymptomatic genetic testing (PGT) for Alzheimer’s disease (AD) is available for at-risk individuals. This study aimed to investigate the public perception of PGT in Saudi Arabia and determine variables that might influence the decision to undergo PGT. A questionnaire link was posted on Twitter by the Saudi Alzheimer’s Disease Association and was made publicly available on social media networks. A total of 2935 people participated, of which 59.9% were willing to undergo PGT. Of these, 26.8% reported having a family history of AD, and 0.24% had two family members with early onset AD. The reasons cited for willingness to undergo PGT included the following: to adopt a healthier lifestyle, to ensure appropriate family and financial planning, to seek early treatment, and to relieve anxiety. In multiple logistic regression analysis, willingness to undergo PGT was negatively associated with having a self-reported family history of dementia (OR 0.81, 95% CI 0.68-0.96) and was positively associated with marital status (OR 1.39, 95% CI 1.13-1.70). In conclusion, PGT for AD seems to be well accepted in this large Saudi cohort. The reasons cited are similar to those reported elsewhere in the literature.