Autistic children and adolescents often have greater difficulty engaging in deception than their non-autistic peers. However, deception in autistic adulthood has received little attention to date. This study examined whether autistic and non-autistic adults differed in their inclination to lie in everyday situations and the factors that underpin this. Forty-one autistic and 41 non-autistic participants completed self-report measures relating to their inclination to lie, ability to lie and moral attitudes about the acceptability of lying. Participants also undertook a reaction-time test of lie-telling, as well as theory of mind and working memory measures. Autistic and non-autistic adults did not significantly differ in their inclination to lie in everyday situations. The degree to which lying was viewed as morally acceptable positively predicted both groups' inclination to lie. The remaining factors underpinning the inclination to lie differed between groups. Lower self-rated lying ability and slower lie speed predicted a reduced inclination to lie in autistic participants, whereas higher theory of mind and working memory capacity predicted a reduced inclination to lie in the non-autistic group. Implications for our understanding of deception in autistic and non-autistic adults are discussed.