This paper presents the findings from a meta-analysis of the motivation of participants in crowdsourcing. We analysed quantitative primary studies of participation in crowdsourcing using metaanalytical statistical techniques. The findings of the meta-analysis are aggregated knowledge claims as far as they can be made based on the analysed studies and the available data. The findings show which intrinsic and extrinsic motivational factors are important, to which degree they are influential, and how much they are dependent on the particular context and type of crowdsourcing.