In this report, we provide a narrative review of existing clinical trial data underlying our current understanding of the toxicities associated with HER2‐targeted ADCs in breast cancer, both as single agent and in combination with other therapies, highlighting common adverse events (AEs)—defined as having occurred in at least 20% of the treatment group receiving the ADC—and serious AEs, defined as grade ≥ 3. The gene discussed is ERBB2; the disease is breast cancer.