Evaluative conditioning (EC) is an experimental paradigm that models the acquisition of attitudes based on co-occurrences between conditioned stimuli (CSs) and unconditioned stimuli (USs). In a typical EC procedure, CS and US are paired several times. However, whether and under which conditions the frequency of such co-occurrences influences the size of the EC effect has not been determined. Given the high theoretical and practical relevance of this question, it is surprising that several decades of research on EC was not able to provide conclusive answers. The present research addresses this long-standing question while taking into account several moderators that help organize the existing literature and inspire new theorizing about frequency effects in EC. Additionally, to achieve high internal validity, we separate mere exposure effects on ratings from frequency effects in EC. Across four experiments, we demonstrate robust frequency effects in EC procedures that provide a different US at each pairing instance. We discuss the results' consequences for theorizing on EC as well as their practical implications.