For more than three decades, cognitive load theory has been addressing learning from a cognitive perspective. Based on this instructional theory, design recommendations and principles have been derived to manage the load on working memory while learning. The increasing attention paid to cognitive load theory in educational science quickly culminated in the need to measure its types of cognitive load — intrinsic, extraneous, and germane cognitive load which additively contribute to the overall load. In this meta-analysis, four frequently used cognitive load questionnaires were examined concerning their reliability (internal consistency) and validity (construct validity and criterion validity). Results revealed that the internal consistency of the subjective cognitive load questionnaires can be considered satisfactory across all four questionnaires. Moreover, moderator analyses showed that reliability estimates of the cognitive load questionnaires did not differ between educational settings, domains of the instructional materials, presentation modes, or number of scale points. Correlations among the cognitive load types partially contradict theory-based assumptions, whereas correlations with learning-related variables support assumptions derived from cognitive load theory. In particular, results seem to support the three-factor model consisting of intrinsic cognitive load, extraneous cognitive load, and germane cognitive load. Results are discussed in relation to current trends in cognitive load theory and recommendations for the future use of cognitive load questionnaires in experimental research are suggested.