Nivolumab is a standard-of-care treatment for relapsed/refractory (r/r) Hodgkin lymphoma (HL) and is approved for selected non-Hodgkin lymphoma (NHL) subtypes. However, high costs significantly restrict nivolumab accessibility, particularly in the developing world. This study aims to report treatment outcomes in patients with r/r HL and r/r NHL treated with standard or reduced doses of nivolumab in Armenia. A total of 16 patients diagnosed with HL and NHL between 2013 and 2023 (follow-up until March 2025) who received at least one nivolumab dose were included in the study. Primary endpoints: overall response rate (ORR), complete response (CR), partial response (PR), and disease progression (PD). Secondary endpoint: overall survival (OS) and safety description. Of the 16 patients, 9 (56.3%) were female. Median age at diagnosis: 37 years. Median follow-up duration: 37 months. Fifteen patients (93.8%) presented with advanced-stage disease. Seven patients (43.8%) were primary resistant. Thirteen (81.3%) experienced financial toxicity, receiving nivolumab at reduced doses. ORR: 9 patients (56.25%), CR: 4 patients (25%), PR: 5 (31.3%), PD: 7 (43.8%). Estimated OS at 12, 24, and 36 months was 91.7%, 81.5%, and 40.7%, respectively. Nivolumab ≥100 mg showed superior efficacy, with responses still seen at reduced doses and no severe adverse events. In conclusion, standard-dose nivolumab showed superior effectiveness in this cohort, though ORR was also observed with reduced doses. Approximately half of patients with r/r HL and NHL responded despite dose reduction. OS and safety were comparable to global data. Larger studies are needed to evaluate potential dose reduction in resource-limited settings.