This study aimed to develop early grade learners' collaborative skills through group work and play-based pedagogy because collaboration is among the twenty-first century's core skills needed among learners. Thus, its development among early-grade learners is paramount, if they are going to fit seamlessly into the twenty-first century. Participatory-action research, as a research design and professional development workshop, guided this study. Three public primary schools (n = 3) and nine teachers (n = 9), who were purposely sampled, constituted the sample for the study. The study was conducted in the Owerri Education Zone, and the data were captured by using semi-structured interviews and learners' performance-rating scales. Respondent validity was employed through member checking to ensure the validity and reliability of the research instrument. Thematic data analysis was used to determine the results and the indings of the study. It was discovered that teachers' knowledge of group work play-based pedagogy was inadequate, thus hampering the development of collaboration skills among early-grade learners. Professional development workshops were mounted to solve the problem through teachers' capacity to use group play-based pedagogy to develop collaborative skills. Among the proffered recommendations was continuous in-service teachers' professional development of current collaborative pedagogical practices that encourage the active participation of early-grade learners.