A number of cognitive abilities have been reported to predict outcome following a non-traumatic acquired brain injury (ABI) in adults. However, the results are inconsistent. Furthermore, the unique and combined capacity of these cognitive abilities to predict ABI outcome has not been evaluated. Consequently, we employed meta-analysis and multiple regression to evaluate the capacity of various neuropsychological domains to predict two separate outcome variables in adults: (1) activities of daily living; and (2) quality of life. Based on the activities of daily living meta-analysis (N = 2384), we estimated the following significant bivariate effects: memory (r = .31, 95% CI: .20/.41]), language (r = .33, 95% CI:.26/.40), attention (r = .38, 95% CI: .30/.46]), executive functions (r = .29, 95% CI: .19/.39]), and visuospatial abilities (r = .41, 95% CI: .34/ .48). Based on the quality of life meta-analysis (N = 1037), we estimated the following significant bivariate effects: memory (r = .12, 95% CI: .03/.20]), language (r = .19, 95% CI: .06/ .32), attention (r = .30, 95% CI: .16/.44]), executive functions (r = .24, 95% CI: .12/.37) and visuospatial/constructional abilities (r = .30, 95% CI: .14/.46). Meta-analytic structural equation modelling (metaSEM) identified two significant, unique predictors of activities of daily living, attention and visuospatial abilities, and the model accounted for 21% of the variance (multiple R2 = .21, 95%CI: .16/.26). For the corresponding quality of life metaSEM, no statistically significant unique predictors were identified, however, a significant multiple correlation was observed, multiple R2 = .11 (95%CI: 04/.18). We conclude that practitioners may be able to predict, with some degree of accuracy, functional outcome following a stroke and other non-traumatic ABI in adults. We also provide some critical commentary on the nature and quality of the measures used in this area of research to represent the cognitive dimensions of interest.