Employing a quasi-experimental design, this study examined the efficacy of humorous idiom video clips on the achievement of Iranian undergraduate students studying English as a Foreign Language (EFL). Forty humorous video clips from the English Idiom Series called "The Teacher" from the BBC website were used to teach 120 idioms to 61 undergraduate students at the University of Bojnord (UB). A 40-item idiom pretest was given to the experimental group (EG) and the control group (CG) while an independent-samples t-test was used to compare the means of these two groups based on posttest scores. A 15-item attitudinal questionnaire captured participants' attitudes toward learning English idioms through video clips. The results indicate that there was a significant difference between the EG and CG mean scores: humorous video clips do facilitate EFL learners' idioms achievement and learners exhibit a positive attitude toward their application in the classroom.