Introduction <p>Women aged ≤40 years with breast cancer have historically undergone overtreatment with extensive surgery. This study compares trends in breast and axillary operations in young patients with breast cancer over time and assesses for surgical de-escalation.</p> Methods <p>Women aged ≤40 years with stage I–III breast cancer who underwent surgery from January 2005 to December 2019 were identified from the National Cancer Database. Patients were divided into two groups to capture trends over time: the 2005–2009 cohort and the 2015–2019 cohort.</p> Results <p>In total, 96,722 evaluable patients with a median age of 36.5 years (range 18–40) were identified. Compared with the 2005–2009 cohort (<i>n</i> = 44,497), the 2015–2019 cohort (<i>n</i> = 52,225) had a higher proportion of early-stage cancers and an increase in hormone receptor-positive breast cancer (<i>p</i> &lt; 0.001). For breast operations, partial mastectomies decreased significantly over time, from 40.8% to 30.2% (<i>p</i> &lt; 0.001). The rate of nipple-sparing mastectomies increased from 0.3% to 9.5%, along with an increased use of reconstruction (<i>p</i> &lt; 0.001). Axillary lymph node dissections (ALNDs) decreased over time, from 37.5% to 19.4% (<i>p</i> &lt; 0.001), with a corresponding increase in the use of radiation (56.3% vs 57.4%, <i>p</i> &lt; 0.001). This trend was pronounced in the node-positive cohort of 29,062 patients who underwent a mastectomy (ALND: 9392 [72.4%] vs 5967 [37.1%]; radiation: 7255 [59.0%] vs 11,757 [75.5%]; <i>p</i> &lt; 0.001). The use of ALND decreased over time, regardless of timing of chemotherapy and type of breast operation (<i>p</i> &lt; 0.001).</p> Conclusions <p>In young patients with stage I–III operable breast cancer, de-escalation of axillary surgery and increased use of radiation is demonstrated.</p>