Teachers' and preservice teachers' attitudes toward students are mental states that may contribute to teachers' judgments and students' achievement. However, in the past, educational research has mainly focused on explicit attitudes and has hardly considered the pivotal role of implicit attitudes in predicting behavior. Drawing on the MODE model of how attitudes guide behavior (Fazio 1990; Fazio and Towles-Schwen 1999), this article gives a brief overview of the most common implicit attitude measures. Focusing on two different student groups who experience disadvantages in educational attainment shows that explicit attitudes are mainly positive, while implicit attitudes are negative and more predictive of teacher' and preservice teachers' behavior. This article highlights the need for implicit measures in educational research and identifies questions to be addressed by future research.