Successful teaching requires that student teachers acquire a conceptual understanding of teaching practices. A promising way to promote such a conceptual understanding is to provide student teachers with examples. We conducted a 3 (between-subjects factor "example format": reading, generation, classification) x 4 (within-subjects factor "type of knowledge": facts, concepts, principles, procedures) experiment with N = 83 student teachers to examine how different formats of learning with examples influence the acquisition of relational categories in the context of lesson planning. Classifying provided examples was more effective for conceptual learning than reading provided examples or generating new examples. At the same time, reading provided examples or generating new examples made no difference in conceptual learning. However, generating new examples resulted in overly optimistic judgments of conceptual learning whereas reading provided examples or classifying provided examples led to rather accurate judgments of conceptual learning. Regardless of example format, more complex categories were more difficult to learn than less complex categories. The findings indicate that classifying provided examples is an effective form of conceptual learning. Generating examples, however, might be detrimental to learning in early phases of concept acquisition. In addition, learning with examples should be adapted to the complexity of the covered categories.