Research has explored many different relationships between contextual influences, such as levels of immigration or economic condition, and attitudes about immigrants, with mixed results. These have largely been international comparative studies using cross-sectional data, therefore they have been unable to make claims about changes in environmental context translating to changes in attitudes of respondents. Furthermore, the previous literature has almost exclusively tested these relationships using data from adults, despite research showing that attitudes are most subject to change during adolescence. This study addresses these issues by using a longitudinal data set of repeated measures of 2,328 German adolescents (about 14–18 years old) over four response waves (2010–2014). Using a multilevel analysis, results show that contextual changes, including the percentage of foreign-born people and unemployment rates within respondents’ states, correspond to changes in attitudes toward immigrants consistent with group threat theory. These results were stable even when controlling individual-level factors.