Abstract The present study investigated the effect of service-learning on English proficiency and attitudes toward learning English among Omani fourth-grade basic education students by gender. Moreover, it investigated teachers' perceptions of service-learning. The study was quasi-experimental in nature, and the sample population consisted of grade 4 basic education students registered in the 2010-2011 academic year. A total of 120 students from four classes in two cycle 1 schools in the Muscat region composed the sample. The two classes in the experimental group were instructed by trained teachers using service-learning, and the two classes in the control group were taught in the normal way. A language proficiency test (the National Test for Grade Four) was used to measure the students' level of proficiency in English. An attitude questionnaire was used to elicit students' attitudes toward learning English. Finally, a semi-structured interview used to elicit teachers' perceptions of service-learning. The validity and reliability of all instruments had previously been established. Students who engaged in service-learning outperformed students in the control group on the proficiency test. In addition, there was a significant difference in the performance of the experimental group compared with the minimum required level of English set by the Ministry of Education. Moreover, girls in the experimental group outperformed boys in the same group. The attitudes of the students in the experimental group changed significantly after the students' engagement in service-learning. This result was supported by the analysis of the teachers interviews. In light of these findings, recommendations are made for further research.