Although the effects of work autonomy (WA) and employee involvement (EI) have been largely studied, their determinants, especially at the macro/institutional level, have attracted much less attention. To better understand (a) the extent to which WA and EI are distinct constructs and (b) the factors that explain their respective levels, this article uses the 2010 European Working Conditions Survey to build sound indexes of WA and EI, provide a picture of the level of both constructs in 33 European countries and analyse their predictors through a multilevel structural model. The results show that WA and EI differ in what concerns their macro-level but not micro-level predictors. Whereas union density and generalized trust strongly influence EI, only generalized trust impacts WA. Documenting that generalized trust as a macro-social trait is powerfully associated with organizational choices is a key contribution of the article.