Since the development of the notion of the teacher-researcher, a range of published action research studies have focused on school-based pedagogy. Scholars agree that action research is an essential tool for teachers to improve their practice, but there is little known about the process underpinning teachers' choice of particular action research methodologies in primary science education. In this systematic literature review, 33 articles were reviewed to examine the methodological considerations teacher-researchers made when conducting action research within the primary school context, as well as the quality of the action plans and the impacts of the research on children's learning in science. The systematic review navigated existing primary science studies, focusing on methodological considerations in the choice of particular types of action research. With regards to the quality of action research studies, the reviewed articles had a good average score for all three types of validity. In terms of the effects of the employed action research methodologies, most studies demonstrated positive impacts on children's learning in science. Based on this review, it is recommended that future researchers be encouraged to carry out action research in their classroom settings, as most authors in the review favour this approach. Researchers should also examine the outcome, process, and democratic validity of their action research studies to generate better quality action plans. Lastly, primary school science teachers can adopt the various action research methodologies employed in this review since most studies support their positive impacts on children's learning in science.