This article presents the results of a survey on the use of digital avatars and agents in museums and places of cultural interest. The optimization of virtual agents in the cultural heritage domain is an interdisciplinary undertaking and this paper investigates pertinent research and solutions and suggests ways forward. The research questions examined relate to (a) the technological characteristics of cultural heritage-related uses of users’ avatars and virtual agents, and patterns that emerge, and (b) suggestions for future research based on this article’s findings. We reviewed relevant publications and analysed the approaches presented to identify trends and issues that could lead to conclusions on the existing state of the field and, moreover, infer and suggest future directions. The main findings relate to a trend toward onsite, sophisticated installations or applications with increasing investment in mixed reality. Moreover, emphasis shifts toward optimising agents such as virtual guides or companions, mediators of cultural content and engaging facilitators. Behavioural Realism (BR), featured mostly in virtual reality installations, greatly fosters engagement according to the reviewed research, and we conclude that mixed reality onsite applications, which are gathering pace, should reach their degree of sophistication and combine the strengths of both MR and BR.