Teaching quality often is assumed to be a personal and stable characteristic of teachers. Whether this is true has scarcely been investigated empirically. In this study the extent to which value-added scores of teachers teaching German and English as a foreign language (EFL) to the same class remain consistent across subjects was investigated. Then, the consistency of two teaching quality dimensions—classroom management and motivational support—across subjects was explored. A sample consisting of 25 classes with 548 students to whom German and EFL were taught by the same teacher was analyzed using multivariate multilevel models and generalizability theory. The results showed that the value-added scores were highly correlated across subjects. While there was hardly any subject-dependent variance in classroom management, there was substantial subject-dependent variance in motivational support. The results indicate that it is important to conduct further studies on the situational and contextual factors that might influence teaching quality to gain a more comprehensive picture regarding the consistency of teaching quality across various conditions.