Ambulatory assessment (AA) studies are becoming more and more popular. However, it can be challenging to motivate participants to comply with study protocols. The aim of the present study was to investigate possible predictors of compliance in AA studies with diverse samples and study designs. To do so, we extracted compliance information, study characteristics, and sample characteristics from 488 previously published studies. The average compliance across the studies was rather high. The total number of measurement occasions and the number of study days were negatively related to the compliance rate. Moreover, a higher percentage of healthy controls in clinical studies was associated with a higher compliance rate. By contrast, other study characteristics (e.g., the amount of financial compensation) and sample characteristics (clinical vs. healthy sample) were not related to compliance. The findings have implications for the design of future AA studies.