This systematic review examined social media research in public relations scholarship in English language between 2015 and 2020 by analyzing 380 articles from 143 journals sampled from multidisciplinary research databases. The analysis focused on research methods, data collection sources, type of social media being studied, use of theoretical frameworks, and differences between PR journals and non-PR journals. Key findings include: (a) PR journals and a few communication journals, which have often been sampled in the existing review studies, contributed to less than half (46.84 %) of the articles included, (b) significant differences between PR journals and non-PR journals in use of survey (X-2 (1, N = 380) = 4.33, p = .04), and use of theoretical frameworks (X-2 (1, N = 380) = 12.70, p < .001), (c) social media (N = 380, 36.6 %), together with platforms that are off social media but online (N = 380, 37.1 %), was the most frequently used data collection source, and (d) about half (N = 380, 47.2 %) of the articles belonged to the lower level on the extent of theoretical framework use continuum. Implications of these findings for future systematic review studies in public relations are discussed.