Although the association between school suspension and deleterious outcomes is widely acknowledged, policy and practice need to be informed by an evidence base derived from multiple studies revealing consistent trends. This meta-analysis aims to address this void by examining the degree to which different types of school suspensions (in-school versus out-of-school) are associated with both academic achievement and school dropout, while concurrently examining study or participant characteristics that moderate these relationships. Data sources included peer-reviewed and non-peer-reviewed studies from 1986-2012 obtained via bibliographic databases. A meta-analysis was conducted on 53 cases from 34 studies. The results revealed a significant inverse relationship between suspensions and achievement, along with a significant positive relationship between suspensions and dropout. Furthermore, study or participant characteristics and type of suspension significantly affected the relationship between suspensions and the outcome variables. Implications for policy, practice, and research are emphasized.