Background: T-cell lymphomas (TCLs) constitute a heterogeneous group of mature T-cell neoplasms characterized by aggressive clinical behavior and poor outcomes, particularly in the relapsed/refractory (R/R) setting. Belinostat is a pan-HDAC inhibitor approved for R/R peripheral T-cell lymphomas. In this retrospective study, we analyze the real-world outcomes of single-agent belinostat in Turkish patients with R/R TCLs. Methods: Patients with R/R TCLs across Turkey who received at least one course of belinostat were included in the study. The primary end point was the overall response rate (ORR). The secondary end points included progression-free survival (PFS), overall survival (OS) and duration of response (DOR). Results: A total of 59 patients with R/R TCL were enrolled in the study, with a median age of 62 years. The median number of previous lines of therapy before belinostat was 2.5. The ORR for belinostat was 30.5% in the overall study cohort. Response assessment was available in 53 patients, among whom the ORR was 34% (18/53). The median PFS was 3 months. The median OS was 12 months, and the median DOR was not reached in responders. At least one adverse event occurred in 39.0% of patients. Conclusions: Belinostat produced objective responses in a subset of patients. These findings support belinostat as a potential individualized treatment option rather than a broadly effective standard for all patients with R/R TCLs. This multicenter real-world study demonstrates that the observed response rates closely mirror those reported in prospective clinical trials, confirming the reproducibility of belinostat efficacy in routine clinical practice.