Conversational agents (CAs) have become integral parts of providers’ service offerings, yet their potential is not fully exploited as users’ acceptance and usage of CAs are often limited. Whereas previous research is rather technology-oriented, our study takes a user-centric perspective on the phenomenon. We conduct a systematic literature review to summarize the determinants of individuals’ acceptance, adoption, and usage of CAs that have been examined in extant research, followed by an interview study to identify potential for further research. In particular, five concepts are proposed for further research: personality, risk aversion, cognitive style, self-efficacy, and desire for control. Empirical studies are encouraged to assess the impact of these user- specific concepts on individuals’ decision to use CAs to eventually inform the design of CAs that facilitate users’ acceptance, adoption, and use. This paper intends to contribute to the body of knowledge about the determinants of CA usage.