The Limited Capacity Model of Motivated Mediated Message Processing (LC4MP) aims to understand message processing dynamics. Despite 20 years of research, no meta-analysis has assessed LC4MP effects. We conducted a meta-analysis of the model to examine three theoretical research domains in the LC4MP: cognitive load, motivation, and memory. Results from 142 articles and 683 effects demonstrate that pooled effect sizes for research domain range from r =.314–.398. Effect sizes vary by measurement modality with self-report resulting in the largest pooled effect size, followed by behavioral, and finally psychophysiological measures. We did not detect evidence of publication bias. These findings offer meta-analytic support for LC4MP research domains and are discussed in terms of falsifiability, predictive and explanatory power.