This intervention study helped EFL learners visualize their possible selves as successful L2 speakers. It included three classes as a control group and three EFL classes as an experimental group at a secondary school in Yemen. The three experimental classes received one ideal L2 self-visualization lesson a week for six weeks, whereas the three control classes received their regular classroom activities. Quantitative and qualitative data were collected. Results of an analysis of covariance indicated that the ideal L2 self, L2 intended learning effort, and L2 learning experience of the experimental group increased significantly, whereas there was no significant increase in those of the control group. Analysis of qualitative data showed that the intervention motivated the students by helping them develop future L2 self-guides, enjoy the L2 learning experience, enhance L2 intended effort, make future plans, goals, and decisions, and recognize the needs to learn English. Pedagogical implications are provided.