This study investigates the effects of in-class and out-of-class involvement as input enhancement strategies on both the paragraph writing proficiency and motivational attitudes of Iranian intermediate EFL learners. Employing a quasi-experimental design, the study was conducted with 60 adolescent female students at the Saba Institute in Mazandaran, Iran. Participants were assigned to two experimental groups and one control group based on their Oxford Placement Test (OPT) results, which identified them as intermediate learners. The in-class involvement group engaged in structured activities such as peer review, teacher-guided discussions, and collaborative revision, while the out-of-class group independently completed structured paragraph-writing tasks outside classroom hours. The control group received conventional instruction based on the coursebook. Data were collected through pretests, posttests, and a validated motivation questionnaire. ANOVA results revealed statistically significant differences in writing performance, with the in-class group outperforming others. Additionally, both experimental groups reported high motivation levels, with the out-of-class group demonstrating slightly stronger motivational outcomes. These findings underscore the dual benefit of involvement strategies in enhancing both writing performance and learner engagement. The study contributes to the growing body of research on EFL writing instruction by highlighting the differential impacts of involvement types. It provides practical implications for curriculum designers and educators seeking to foster both academic achievement and motivation through contextually appropriate pedagogical strategies.