People vary in the extent to which they present themselves authentically online. This study applied Uses and Gratifications Theory to investigate the utility of grandiose narcissism, vulnerable narcissism, primary psychopathy, secondary psychopathy, and Machiavellianism in predicting authentic self-presentation on Instagram. Participants (N = 542; 62.9% women; 60.1% Australian) with a currently active Instagram account were recruited via social media advertisements and completed an online questionnaire assessing personality and authenticity. Instagram authenticity was operationalised as Euclidean distances between the true self and the Instagram self. Results partially supported hypotheses, with higher levels of trait vulnerable narcissism and Machiavellianism predicting less congruence between the true self and the Instagram self (i.e., inauthenticity). Grandiose narcissism, primary psychopathy, and secondary psychopathy were not significant predictors of authentic self-presentation on Instagram. Findings of the current study extend previous research exploring authentic self-presentation on social media and are interpreted in line with uses and gratifications. We recommend further exploration of variation in authentic self-presentation on Instagram, from normative forms to outright deception.