Background: Practice tests have been shown to be an effective means to foster long-term retention in higher education, at least compared to restudying (i.e., the testing effect). Objective: The present study replicated and extended prior research by examining whether and to what extent the positive effects of testing on long-term retention in a typical psychology lecture transfer to content presented only during initial learning (and not practiced). Method: Using a within-subjects design, we alternated post-lecture multiple-choice practice tests and restudying opportunities in two psychology classes (N=67). One week after the final lecture session of a cycle of six weekly lecture sessions, retention of learning content was assessed by comparing performance on questions referring to content practiced via testing, encountered via restudying, or unreviewed. Results: We found a testing effect for practiced content, whereas no transfer effect occurred for untested content from the same lecture sessions. Conclusion: These results show that the testing effect is a powerful learning tool, but also suggest a possible boundary condition pertaining only to explicitly tested content. Teaching Implications: Practice testing should be integrated regularly in higher education courses to foster long-term retention for a final test. However, educators should take care that important content is fully covered in practice tests.