In recent decades, numerous studies have suggested a positive relationship between prosociality and well-being. What remains less clear are (a) what the magnitude of this relationship is, and (b) what the moderators that influence it are. To address these questions, we conducted a meta-analysis to examine the strength of the prosociality to well-being link under different operationalizations, and how a set of theoretical, demographic, and methodological variables moderate the link. While the results revealed a modest overall mean effect size (r = .13, K = 201, N = 198,213) between prosociality and well-being, this masked the substantial variability in the effect as a function of numerous moderators. In particular, the effect of prosociality on eudaimonic well-being was stronger than that on hedonic well-being. Prosociality was most strongly related to psychological functioning-showing a more modest relationship with psychological malfunctioning and physical health. Using prosociality scales was more strongly associated with well-being than using measures of volunteering/helping frequency or status. In addition, informal helping (vs. formal helping) was linked to more well-being benefits. Demographically, younger givers exhibited higher levels of well-being other than physical health, while older and retired givers reported better physical health only. Female givers showed stronger relationships between prosociality and eudaimonic well-being, psychological malfunctioning, and physical health. Methodologically, the magnitude of the link was stronger in studies using primary (vs. secondary) data and with higher methodological rigor (i.e., measurement reliability and validity). We discussed all of these results and implications and suggested directions for future research. (PsycInfo Database Record (c) 2020 APA, all rights reserved).