**Abstract** Dehumanization is the denial of full human potential to an individual or a social group. Although it is widely seen as a grave social ill, the psychological roots of dehumanization are not yet clear. In the present research, we examined the role of agency and communion. These dimensions are pivotal in perceiving other people, and we hypothesized that they might be crucial to viewing people as fully human. In eight experiments, we manipulated agency or communion using either videos of interacting geometric shapes or by manipulating static images of faces showing different degrees of agency and communion. Participants rated the degree of humanness of presented targets. Across the studies and in meta-analyses (N = 758 for agency and N = 776 for communion), agency but not communion had systematic effects on humanness ratings. Granting agency might therefore limit dehumanization. **Short descriptions of the studies 1-5:** 1. **Study 1: The Impact of Agency on Humanness Judgments**: To estimate the role of agency in humanness ratings, we constructed a manipulation representing the notion of agency through the movement of a geometric shape. In Study 1 we focused on the perception of an individual target. 2. **Study 2a: The Impact of Agency on Humanness Judgments of Groups**: This study replicated the Study 1 in a group context. 3. **Study 2b: The Impact of Agency on Humanness Judgments of Groups**: In this study, we replicated the Study 2a with a new set of films. This study was pre-registered at [https://osf.io/nwf5x/register/5771ca429ad5a1020de2872e][1]. 4. **Study 3a: The Impact of Communion on Humanness Judgments of Groups**: Studies 1-2b examined the sole role of agency. To estimate the unique role of communion in humanness ratings, we used a similar procedure and constructed a manipulation representing the notion of communion through the movement of geometric shapes. Given the relational nature of communion, we used only group targets in the manipulation. This study was pre-registered at [https://osf.io/2dwzb/register/5771ca429ad5a1020de2872e][2]. 5. **Study 3b: The Impact of Communion on Humanness Judgments of Groups**: This study is a direct replication of Study 3a. This study was pre-registered at [https://osf.io/2dwzb/register/5771ca429ad5a1020de2872e][3]. 6. **Study 3c: The Impact of Communion on Humanness Judgments of Groups**: This study is a direct replication of Study 3a and 3b using a different humanness scale. This study was pre-registered at [https://osf.io/xmuzt/register/5771ca429ad5a1020de2872e][4]. 7. **Study 4: The Joint Impact of Agency and Communion on Humanness Judgments of Groups**: Studies 1-3c examined the unique role of agency or communion. In Study 4, we aimed to assess the possible interactive effects of the two dimensions. This study was pre-registered at [https://osf.io/5mgsc/register/5771ca429ad5a1020de2872e][5]. 8. **Study 5: The Impact of Agency and Communion on Humanness Judgments**: In Studies 1-4, we used abstract stimuli to examine the role of agency and communion in humanness ratings. Such a method was indispensable to examine general factors that affect humanness ratings but do not depend on an actual context. In Study 5, we wanted to examine whether the results obtained in our studies of abstract stimuli generalize to realistic stimuli. To do this, we used a previously validated approach to systematically manipulate the perception of communion and agency from faces (Walker & Vetter, 2015) with a novel set of faces that were photographed recently to build the Basel Face Database (Walker, Schönborn, Greifeneder, & Vetter, under review). This choice of manipulation allowed us to replicate the effects obtained in Studies 1-4 and to compare the findings from these studies, obtained using abstract stimuli, to findings obtained using highly meaningful ecologically valid stimuli. [1]: https://osf.io/nwf5x/register/5771ca429ad5a1020de2872e [2]: https://osf.io/2dwzb/register/5771ca429ad5a1020de2872e [3]: https://osf.io/2dwzb/register/5771ca429ad5a1020de2872e [4]: https://osf.io/xmuzt/register/5771ca429ad5a1020de2872e [5]: https://osf.io/5mgsc/register/5771ca429ad5a1020de2872e