Considering one of the earliest calls for applying pragmatics in the second language, Kasper and Rose’s (2002) study “Is Pragmatic Teachable?”, pragmatic features have been analyzed during the last 20 years in EFL/ESL contexts. The amalgamation of studies has been conducted on many speech acts around the world within the two decades, among which apology is considered as the second most-appreciated speech act in Iran. The aim of the current meta-analysis is twofold: first, to unravel the overall effectiveness of the instruction in an Iranian EFL context on the speech act of apology, and second, to explore whether treatment types and research designs moderate this effectiveness. To this end, out of a total number of 31 studies, 12 papers were chosen based on the exclusion and inclusion criteria, which were coded for the analysis. The results of the study revealed that the instruction of apology is effective for this speech act, and it documented a medium effect size. Furthermore, it was found that research design is a good predictor for this effectiveness, and the quasi-experimental group displayed a large (g = 2.39) and positive effect. Although treatment types (e.g., explicit & non-explicit) produced medium and large effect sizes, they are not a suitable predictor for the overall effectiveness of instruction on the aforementioned speech act. The study concludes with pedagogical implications and suggestions for future studies.
