This study examines the relationship between resilience, collaboration, and language learning strategies (LLS) in developing L2 oral proficiency in short-term study-abroad (STSA) programs. While studying abroad provides a linguistically rich environment for L2 learning, individual and social factors also influence oral proficiency gains. Collaboration, defined here as learners’ general tendency to actively engage with peers in cooperative activities to solve language-related problems or achieve communicative goals, is one factor that may significantly shape learning outcomes. This study investigates how resilience and collaboration contribute to L2 oral proficiency development, both directly and indirectly, via LLS. Ninety-two Japanese university students participated in four-week STSA programs, completed pre- and post-oral proficiency exams, and responded to surveys assessing resilience, collaboration, and LLS. Path analysis indicated that resilience had a direct and significant impact on L2 oral proficiency and was moderately associated with collaboration. Collaboration emerged as a strong predictor of oral proficiency gains, underscoring the importance of peer interaction and social engagement in short-term immersion. However, LLS did not significantly mediate the relationship between resilience, collaboration, and oral proficiency, suggesting that fostering collaborative engagement and resilience may be more beneficial than explicit strategy instruction within STSA contexts.