<p>The present study investigates the mediating role of attitude towards English language and the effect of metacognitive vocabulary learning strategy instruction on the recall of collocations. To this end, 75 upper-intermediate EFL participants reflecting positive and negative attitudes (+A and -A) based on Attitude/Motivation Test Battery) towards language were randomly assigned into two control and experimental groups. They both received the same type of collocation instruction, but the experimental group, additionally, received the metacognitive explicit strategy instruction. A pretest and a posttest measuring the learners' collocation knowledge before and after treatment were administered. A two-way ANOVA was run to compare the two groups plus the effect of language attitude on such performance. The results indicated that treatment did have an effect on the recall of collocations and also the +A learners outperformed their -A counterparts.</p>