There is limited research regarding university students' academic achievement and what influences it. We argue that university students' academic achievement could be influenced by different factors to those observed for schoolchildren. We investigated whether university students' beliefs about intelligence ('implicit theories'), self-efficacy and basic psychological needs satisfaction could explain their academic achievement. 203 students completed measures of implicit theories, self-efficacy and basic psychological needs, and provided their course grades via an online survey tool. Structural equation modelling was used to analyse the data. University students' implicit theories were indirectly associated with their academic achievement via self-efficacy. Basic psychological needs satisfaction was positively associated with self-efficacy and there was an indirect relationship between basic psychological needs satisfaction and academic achievement. Theories regarding the relationship between implicit theories and academic achievement need to be amended to account for the role of self-efficacy and basic needs satisfaction for adult learners.