Background/Objectives: Diffuse large B-cell lymphoma (DLBCL) and high-grade follicular lymphoma (FL) are aggressive B-cell malignancies predominantly affecting older adults. R-CHOP remains the frontline standard of care, with frail and elderly patients requiring attenuated regimens such as R-mini-CHOP. Real-world comparative data in elderly and Hispanic populations remain limited. We aimed to evaluate outcomes of R-mini-CHOP versus R-CHOP in elderly patients and to explore potential differences by ethnicity. Methods: Single-center retrospective analysis of adult patients older than 70 years with DLBCL and high-grade FL, treated between January 2014 and June 2025. Clinical characteristics, treatment responses, and survival outcomes were analyzed. The overall survival (OS) and progression-free survival (PFS) were estimated using the Kaplan–Meier method. Results: A total of 136 patients were included (72 R-mini-CHOP; 64 R-CHOP). Patients receiving R-mini-CHOP were older (median 82 vs. 74 years) and had higher-risk features. Overall response rates were 88.7% and 92.6% in the R-mini-CHOP and R-CHOP groups, respectively. Two-year OS was 79.3% for R-mini-CHOP and 76.7% for R-CHOP. Median OS and PFS were not reached in either group. Elevated lactate dehydrogenase (LDH) was associated with an inferior response. We identified a trend toward better response with R-CHOP in Hispanic patients, although this was not statistically significant. Conclusions: In this real-world cohort, R-mini-CHOP achieved response and survival outcomes comparable to R-CHOP despite worse baseline characteristics. These findings support the use of dose-attenuated therapy in frail and elderly patients and suggest that equitable access to care may mitigate ethnic disparities in outcomes.