In Ontario, recently arrived English as a second language (ESL) immigrant students are frequently excluded from participating in the Grade 9 core French program, which is obligatory in principle for all secondary school students. I designed a mixed-method study to explore whether this practice, where it occurs, is well founded. First, through a survey of the secondary principals and guidance heads of a large urban southern Ontario school board, I examined the present practices of inclusion of ESL students in core French. Second, I compared the French proficiency of three, groups of secondary students: recently arrived ESL adolescents, multilingual Canadian-born students and unilingual Canadian-born students. Third, this study examined the contributions the ESL participants brought to the French-learning context by means of participant journals, participant and parental interviews. The survey of the principals and guidance heads revealed that French was considered an optional course for ESL students. The French proficiency measures, however, demonstrated the ESL students' ability to be successful in core French. French proficiency was measured using a multi-skills test consisting of a multiple choice listening test, three reading tasks, two writing tasks, a dictation and three oral tasks. The ESL group outperformed the other groups in one writing task and in both the reading and listening test components. They also outperformed the unilingual group on one section of the speaking test and the multilingual group on another section of the speaking component. There were no significant differences found among the groups for the other test components: the dictation, the second writing section or the final speaking component. The qualitative findings reveal that the ESL participants were confident in their ability to learn French. This confidence was founded in their prior successful language-learning experiences. Moreover, the ESL participants expressed satisfaction in their progress in learning French after one semester of study. Their positive affect was grounded in their view of multilingualism that tolerates and celebrates different levels of competence in multiple languages. In addition, they attributed value to learning French as one of the official languages of Canada.