Background: Most breast cancer clinicians lack training to counsel patients about sexual concerns. The purpose of this study was to assess the feasibility, acceptability, and preliminary effects of a mobile learning (mLearning) intervention (improving Sexual Health and Augmenting Relationships through Education [iSHARE]) aimed at enhancing breast cancer clinicians’ knowledge of, beliefs about, and comfort with discussing patients’ sexual health concerns. Methods: Clinicians listened to a 2-part educational podcast series offering information on breast cancer–related sexual health concerns and effective communication on the topic, which consisted of interviews with expert guests. Intervention feasibility was assessed through rates of enrollment, retention, and intervention completion, with benchmarks of 40%, 70%, and 60%, respectively. Acceptability was assessed through program evaluations, with 75% of clinicians rating the intervention favorably (eg, relevance, satisfaction) signifying acceptability. Clinicians self-reported their knowledge about breast cancer–related sexual health concerns, beliefs (ie, self-efficacy for discussing sexual health concerns), and comfort with discussing sexual concerns measured at preintervention and postintervention. Qualitative analysis examined clinicians’ perceptions of lessons learned from the intervention. Results: A total of 32 breast cancer clinicians enrolled (46% of those invited; 97% of those who responded and screened eligible), 30 (94%) completed both the intervention and study surveys, and 80% rated the intervention favorably, demonstrating feasibility and acceptability. Results showed positive trends for improvement in clinician knowledge, beliefs, and comfort with discussing sexual health concerns. Clinicians reported key lessons learned, including taking a proactive approach to discussing sexual health concerns, normalizing the topic, addressing vaginal health, sending the message that help is available, and assessing sexual health concerns with patients from different backgrounds. Conclusions: Breast cancer clinicians were amenable to participating in the iSHARE intervention and found it useful. iSHARE showed promise for improving clinician’s knowledge and comfort discussing patients’ sexual health concerns. A larger trial is required to demonstrate efficacy. Future studies should also examine whether iSHARE can improve patient–clinician communication and address patients’ sexual concerns.