Purpose: This study investigates how Cantonese language experience influences the potential effects of (a) musicianship and (b) musical ability on English stress perception. Method: The sample contained 124 participants, evenly split into Cantonese musician, Cantonese nonmusician, English musician, and English nonmusician groups. They completed the English stress discrimination task, English stress sequence recall task, Musical Ear Test, and nonverbal intelligence task. Following the musicianship-based analysis, 44 Cantonese and English listeners were reassigned to four groups based on their musical ability--Cantonese high musical ability, Cantonese low musical ability, English high musical ability, and English low musical ability groups. Results: Musicianship-based analysis on English stress perception revealed a significant interaction between musicianship and language. Specifically, musicians outperformed nonmusicians only among the English but not the Cantonese listeners. By contrast, ability-based analysis showed significant main effects of musical ability and language. For both Cantonese and English listeners, those with a high musical ability outperformed those with a low musical ability. Regardless of musical ability, Cantonese listeners outperformed English listeners. Correlational analyses yielded consistent findings. Conclusions: This study has found cross-sectional evidence that musical ability, but not musicianship, facilitates Cantonese English as a second language (ESL) listeners' English stress perception. From a theoretical perspective, the current findings motivate two potential additions to the OPERA (Overlap, Precision, Emotion, Repetition, and Attention) hypothesis for music-to-language transfer--unsaturation and utilization. Practically, the findings cast doubt on the application of nonperceptual based instrumental music training to enhance Cantonese ESL learners' perceptual learning of English stress.