Data supporting the use of etoposide-based therapy in hemophagocytic lymphohistiocytosis (HLH) arise largely from pediatric studies. There is a lack of comparable data among adult patients with secondary HLH. We conducted a retrospective study to assess the impact of etoposide-based therapy on outcomes in adult secondary HLH. The primary outcome was overall survival. The log-rank test was used to compare Kaplan-Meier distributions of time-to-event outcomes. Multivariable Cox proportional hazards modeling was used to estimate adjusted hazard ratios (HRs) with 95% confidence intervals (CIs). Ninety adults with secondary HLH seen between January 1, 2009, and January 6, 2020, were included. Forty-two patients (47%) received etoposide-based therapy, while 48 (53%) received treatment only for their inciting proinflammatory condition. Thirty-three patients in the etoposide group (72%) and 32 in the no-etoposide group (67%) died during follow-up. Median survival in the etoposide and no-etoposide groups was 1.04 and 1.39 months, respectively. There was no significant difference in survival between the etoposide and no-etoposide groups (log-rank p = 0.4146). On multivariable analysis, there was no association between treatment with etoposide and survival (HR for death with etoposide = 1.067, 95% CI: 0.633–1.799, p = 0.8084). Use of etoposide-based therapy was not associated with improvement in outcomes in this large cohort of adult secondary HLH patients.