The article presents results of a study on teachers' views, beliefs, and experience on school-based informal collaboration for professional improvement. It explores the relationship of teacher beliefs in the collective efficacy of their colleagues and school's capital and culture with their beliefs and experience in school-based collaborative learning. The key source of evidence used is a survey of 1025 primary and secondary teachers in three geographical regions of Chile. Main results show that teachers hold positive beliefs about the collective efficacy of their colleagues and students in their schools but more negative ones regarding the contribution of parents. In terms of collaboration, teachers hold positive beliefs in general about its role for professional learning but indeed engage more in the "weaker" types of collaboration such as "sharing ideas" and "talking about teaching problems" and less in the more demanding ones such as "mutual lesson observation" and "team teaching." Differences in teachers' views, beliefs, and experience were examined in terms of level of teaching (primary/secondary), urban/rural location, school type (public and private), and school size.