This study represents the findings of a systematic review (SR) of literature in the teacher professional development (TPD) domain to outline the research patterns through content examination of 199 research articles (RAs) in the area of TPD over the previous 40 years (1982 -2021). RAs were investigated and their research content areas, utilized research methods, data collection procedures, and findings were analyzed and coded. The broad investigation of the RAs showed a wide variety of themes that corresponded to 22 research areas. TPD program effects, TPD & technology, and TPD & Sociolinguistics were the most searched content areas. It was also found that the qualitative method with 52.26% of occurrences appeared to be the dominant research method used in RAs. Exploring data collection procedures, it was uncovered that interview, questionnaire and observation were the main data collection strategies utilized within the TPD RAs. Analyzing the findings, changes in teacher practices, attitudes and knowledge, learner achievements, and determining priorities for TPD programs were the most reported findings in TPD RAs. This corpus-driven SR underpins the notion that TPD makes a difference in altering teachers’ practices and attitudes and improves learner abilities if specific characteristics are taken into account in the planning and administration of TPD programs.
