Considering the significant role of vocabulary in learning a language, and teachers' great responsibility in providing opportunities to facilitate this learning, many studies have focused on the best means of achieving a good knowledge of vocabulary. This study set out to investigate the effect of four post-teaching activities, namely game, narrative writing, role-play, and speaking tasks on vocabulary gain of elementary Iranian EFL learners across gender. The sample in the study was composed of 111 elementary adult EFL learners assigned into four experimental groups for females and four experimental groups for males as well as two control groups one for each gender, at AVA Talk Institute, Urmia, Iran. Successive to the pre-test, which was meant to measure the learners' prior knowledge of the target words, learners were asked to carry out the required tasks using the words they were provided with. The results of two-way ANOVA analysis indicate statistically significant main effects for vocabulary learning across different activity types with role-play leading to the highest vocabulary gain (M=19.27, SD=3.70). Moreover, the gender of participants has a significant [F (1, 168) =28.40, p=.000] impact upon the vocabulary learning of the participants, with female learners outperforming their male peers. The results of the study have implications for EFL teachers and provide them with new insights into implementing task-oriented activities for better retention of vocabulary.