Based on the increasing interest in systematic reviews and meta-analyses of Single-Subject Experimental Designs (SSEDs), the aim of the present review is to determine the general characteristics of these meta-analyses, including design characteristics of the primary studies and the meta-analyses, the kind of data, and the kind of analysis. After a systematic search for studies, 178 studies were examined for various features. The results indicated that the number of SSED meta-analyses and reviews has increased remarkably in recent years. The most frequently used effect size metric was percentage of non-overlapping data (PND) and the most commonly utilized analysis for synthesizing the results of primary SSEDs was a simple average of effect sizes. Based on the findings of the present review, some implications for future SSED meta-analyses are proposed.