This study examined the effect of play-based practices implemented with a national project on the development of Turkish primary school teachers' perceptions of play. Thirty primary school teachers participated in the study, and the play-based applications lasted six days. Sample play activities were taught to the teachers, and then they were asked to produce their own. The perception of play scale was used to examine the effects of the applications on perceptions of play. In addition, semi-structured interviews were conducted to examine the changes in individuals more clearly. Teachers' perceptions of play were examined in terms of the contributions, tasks, and nature of play activities. Nonparametric tests were used in the analysis of quantitative data, and content analysis was used in the analysis of qualitative data. As a result of this study, positive changes were seen in the teachers' perceptions of play.