Most skills acquired through on-the-job training may be specific to an occupation and therefore transferable to some but not all firms. This paper explores the relationship between the size of the local market for an occupation-specific skill and job-training outcomes. The Stevens (1994) model of training predicts that as market size increases, job turnover increases and training becomes more general. I test these predictions using data on blue-collar workers and variation in market size across U.S. metropolitan areas. The empirical results support the theoretical predictions and the impacts are most relevant at low levels of market size.