<p>The seductive details effect on learning outcomes has garnered increasing scholarly attention; however, empirical findings remain inconsistent. Although cognitive load theory is frequently used to explain this effect, the specific mediating roles of intrinsic, extraneous, and germane cognitive load are still under explored. This multi-level meta-analysis investigates the overall impact of seductive details on learning outcomes and their sub-components—recall, comprehension, and transfer—and examines the mediating roles of different types of cognitive load. Drawing on 177 effect sizes from 50 studies, the results indicate that: (a) seductive details have a small but statistically significant negative effect on overall learning outcomes (<i>g</i> = −0.16); (b) the negative effects are observed for comprehension (<i>g</i> = −0.19), recall (<i>g</i> = −0.17), and transfer (<i>g</i> = −0.12); (c) sample size, language of seductive text, and learning environment significantly moderate the effect of seductive details; and (d) seductive details undermine learning outcomes primarily by increasing extraneous cognitive load, whereas intrinsic and germane cognitive load do not play significant mediating roles. This meta-analysis advances the precision of the seductive details effect, clarifies the mechanisms through which seductive details hinder learning, and highlights the instructional value of paper-and-pencil learning settings. It further recommends minimizing extraneous cognitive load by reducing irrelevant or decorative elements in instructional materials.</p>