The present research examined the effect of title selection tasks as post reading activities on learners' vocabulary achievement. A quasi-experimental design was adopted with a pre, intervention and a posttest. Participants were selected via a placement test and randomly assigned into two equal groups. After administering the pretest of vocabulary, the participants attended treatment sessions. The experimental group received reading passages without titles while they guessed the title for the passages without title. But the control group was taught conventionally and read the passages with titles and did the exercises. After the intervention sessions, both groups took the posttest of vocabulary and data were collected to compare the groups' means in the pre and posttest. Results indicated that the experimental group significantly outperformed the control one. Implications of the study suggest that English as a foreign language (EFL) teachers may use post reading activities like title selection to boost vocabulary learning since the learners try to focus on the passage main idea and guess the exact title for the passages.