Much work has been conducted to investigate the obstacles that keep users from using mitigations against security and privacy threats on smartphones. By contrast, we conducted in-depth interviews (N = 19) to explore users’ motivations for voluntarily applying security and privacy actions on smartphones. Our work focuses on analyzing intrinsic motivation in terms of psychological need fulfillment. The findings from the interview study provide first insights on the salience of basic psychological needs in the context of smartphone security and privacy. They illustrate how security and privacy actions on smartphones are motivated by a variety of psychological needs, only one of them being the need for Security. We further conducted an online survey (N = 70) in which we used questionnaires on psychological need fulfillment from the literature. The online survey is a first attempt to quantify psychological need fulfillment for security and privacy actions on smartphones. Whereas the results of the interview study indicate that Security and other needs play a role as motivators for employing security and privacy actions on smartphones, the online study does not support the need for Security as an outstanding motivator. Instead, in the online study, other needs such as Keeping the meaningful, Stimulation, Autonomy, and Competence show to be rather salient as motivators for security and privacy actions. Furthermore, the mean need fulfillment for security and privacy actions is in general rather low in the online survey. We conclude that there is scope for improvement to maximize psychological need fulfillment with security and privacy actions. In order to achieve a positive user experience with security and privacy technologies on smartphones, we suggest addressing additional psychological needs, beyond the need for Security, in the design of such technologies.