This study determined the effects of peer influence on students’ motivation among high school students in Maryknoll School of Sigaboy, Inc. in Governor Generoso, Davao Oriental, Philippines. Using stratified random sampling, this study employed a sample of 172 high school students from the total population. Data was collected through a modified survey questionnaire. Results reveal very high levels of peer influence which yielded a mean of 4.23 and students’ motivation of 4.30. Furthermore, regression was used to test the influence of peer influence to students’ motivation which yielded an f-value of 0.00. This result reveals that peer influence significantly affects motivation of students in MSSI. Furthermore, this study concludes a notion that any adjustment made on peer influence has a positive or negative effect to students’ motivation. This simply implies that peers have effects to the students’ motivation in learning and interaction in school. Moreover, this study recommends improving peer influence positively because this would positively affect students’ enthusiasm toward development. Thus, it is essential to strengthen and enhance the implementation of Peer Club and its relevant activities in schools most especially in MSSI.