Background: Early treatment (tx) improves survival in rectal cancer (ca). We explored whether socioeconomic and demographic attributes are associated with time to tx initiation for rectal ca patients (pts) in New York's largest and most diverse healthcare system. Methods: 283 rectal ca pts were identified from three multidisciplinary tumor boards from 2019-2022. Time to tx was calculated as time from biopsy to first tx (surgery, chemotherapy, or radiation). Social work assistance was defined as an intervention by a social worker for home care, housing, or transportation assistance. Reasons for tx delay were assessed from physician and social work notes. Results: Median time to tx for all pts was 41 days. Time to tx was longer for Black/African American (BAA) (56.5 days; p < 0.001) and Medicare only (46.5 days; p = 0.005) pts. No differences were seen in time to tx for all pts when stratified by first tx modality (surgery, chemotherapy, or radiation). In a univariable linear regression, BAA pts (vs Asian or White; p < 0.001), Medicare only pts (vs Medicaid, Medicare with Supplemental, or Commercial Insurance; p = 0.001), and pts requesting social work assistance (p = 0.001) predicted longer time to tx. Employed pts (vs unemployed or retired; p = 0.034) predicted shorter time to tx. In a multivariable model, BAA (p = 0.013), Medicare (p = 0.022), and social work assistance (p = 0.029) predicted longer time to tx. The most common reasons identified for tx delay in BAA and Medicare pts were hospitalization during diagnosis (9%), evaluation of metastatic disease (9%), and tx hesitancy (7%). The odds ratio of being hospitalized during initial workup was 2.8 times higher for BAA than Asian or White pts (p = 0.007). Conclusions: Analysis of time to tx in rectal ca showed a notable delay for BAA pts, Medicare only pts, and pts requesting social work assistance. These findings may empower further studies to assess which factors are causal and to implement interventions that promote equity in timely tx for rectal ca pts. Reasons for tx delay were also not well documented and should be further elucidated.