Background and Objectives: A previous analysis of breast cancer care after the 2014 Medicaid expansion in Kentucky demonstrated delays in treatment despite a 12% increase in insurance coverage. This study sought to identify factors associated with treatment delays to better focus efforts for improved breast cancer care.Methods: The Kentucky Cancer Registry was queried for adult women diagnosed with invasive breast cancer between 2010 and 2016 who underwent up-front surgery. Demographic, tumor, and treatment characteristics were assessed to identify factors independently associated with treatment delays.Results: Among 6225 patients, treatment after Medicaid expansion (odds ratio [OR] = 2.18, 95% confidence interval [CI] = 1.874-2.535, P < .001), urban residence (OR = 1.362, 95% CI = 1.163-1.594, P < .001), treatment at an academic center (OR = 1.988, 95% CI = 1.610-2.455, P < .001), and breast reconstruction (OR = 3.748, 95% CI = 2.780-5.053, P < .001) were associated with delay from diagnosis to surgery. Delay in postoperative chemotherapy was associated with older age (OR = 1.155,95% CI = 1.002-1.332, P = .0469), low education level (OR = 1.324, 95% CI = 1.164-1.506, P < .001), hormone receptor positivity (OR = 1.375, 95% CI = 1.187-1.593, P < .001), and mastectomy (OR = 1.312, 95% CI = 1.138-1.513, P < .001). Delay in postoperative radiation was associated with younger age (OR = 1.376, 95% CI = 1.370-1.382, P < .001), urban residence (OR = 1.741, 95% CI = 1.732-1.751, P < .001), treatment after Medicaid expansion (OR = 2.007, 95% CI = 1.994-2.021, P < .001), early stage disease (OR = 5.661, 95% CI = 5.640-5.682, P < .001), and mastectomy (OR = 1.884, 95% CI = 1.870-1.898, P < .001).Conclusions: Patient, tumor, and socioeconomic factors influence the timing of breast cancer treatment. Improving timeliness of treatment will likely require improvements in outreach, education, and healthcare infrastructure.