Are Emotion-Expressing Messages More Shared on Social Media? A Meta-Analytic Review OPEN ACCESS Top-Quality Science Peer Reviewed Open Peer Reviewed Review of Communication Research 2022, Vol.10 ISSN: 2255-4165 Abstract Given that social media has brought significant change to the communication landscape, researchers have explored factors that can influence audiences’ information-sharing on social media such as a message feature like emotion-expressing. The present study meta-analytically summarized 19 studies to advance the understanding of the associations between emotion- expressing messages and information-sharing on social media in health and crisis communication contexts. Additional moderator analyses considered social media platform, sampling method, coding method, and emotion valence. Our study showed support for the social sharing of emotion hypothesis on social media; the findings showed that emotion-expressing messages are more likely to motivate audiences’ sharing behavior on social media in health and crisis contexts ( r = .09, k = 19, N = 4,582,823). Moreover, we found that studies focusing on non-Twitter platforms (vs. Twitter), using nonrandom sampling (vs. using random sampling or all samples), using human coding (vs. machine coding), and focusing on messages expressing positive emotions (vs. negative emotions or both positive and negative emotions) had larger effect sizes. The study sug- gested implications for the future development of a theoretical framework on emotion-expressing messages and information- sharing. It also informed communication practices of broadening the reach of health and crisis information. Suggested citation: Chen, J., Yan, Y., & Leach, J. (2022). Are Emotion-Expressing Messages More Shared on Social Media? A Meta-Analytic Review. Review of Communication Research, 10, pp. 59–79. https://doi.org/10.12840/ISSN.2255-4165.034 Keywords: social media, social sharing of emotion, health communication, crisis communication, meta-analysis Editor: Nathan Walter (Northwestern University, USA). Reviewers who accepted to sign their review: Jiyoung Lee (The University of Alabama, USA) and Renwen (Alice) Zhang (National University of Singapore, Singapore). Junhan Chen University of Maryland, USA jchen134@umd.edu Accepted: Dec. 2021 Prepublished: Jan., 23 th 2022 Received: Jun. 2021 Published: Mar. 2022 Yumin Yan University of Maryland, USA yyan1006@umd.edu John Leach University of Maryland, USA jleach@umd.edu