This contribution investigates what motivates the use of European Union (EU) law at the street level of migration law implementation. The street level is a crucial venue for EU implementation because lower-level implementers critically influence the level of EU compliance eventually achieved. Employing a bottom-up approach towards implementation, the article combines insights from social psychology and the street-level literature to develop expectations about the relation between individuals' motivations and their use of EU law. The study investigates through qualitative interviews to what extent German migration administrators use EU law in three multilevel decision contexts. The main findings are that uses of EU law vary across contexts and individual implementers. Particularly when national regulatory frameworks are ambiguous, substantive moral norms and instrumental motivations trigger some implementers to rely on EU law. This reliance even has the potential to correct for problematic transposition.