The optimal minimally invasive surgical approach to mediastinal tumors is unknown. There are limited reports comparing the outcomes of resection with robotic-assisted thoracoscopic surgery (RATS) and video-assisted thoracoscopic surgery (VATS) surgery. We hypothesized that patients who underwent RATS would have improved outcomes. The National Cancer Database was queried for all patients who underwent a minimally invasive surgical approach for any mediastinal tumor from 2010 to 2016. Patients were determined to have an adverse composite outcome if they had any of the adverse perioperative outcomes: conversion to open procedure, 90-day mortality, 30-day readmission, and positive pathologic margins. Secondary outcomes of interest were length of stay and overall survival. Multivariable logistic regression was used to assess likelihood of having a composite adverse outcome based on surgical approach. The study included 856 patients: 402 (47%) underwent VATS and 454 (53%) underwent RATS. RATS resections were associated with fewer conversions (4.9% vs 14.7%, P < .001), fewer positive margins (24.3% vs 31.6%, P = .02), shorter length of stay (3.8 days vs 4.3 days, P = .01), and fewer composite adverse events (36.7% vs 51.3%, P < .001). Multivariate analysis showed RATS (odds ratio, 0.44; P < .001) was independently associated with a decreased likelihood of a composite adverse outcome, even among tumors exceeding 4 cm (odds ratio, 0.45; P = .001). Overall survival was similar between the 2 groups. Among patients who underwent a minimally invasive surgical approach for a mediastinal tumor, RATS had fewer adverse outcomes than VATS, even for tumors 4 cm or larger. These data suggests that RATS may be the preferred technique for patients who are candidates for minimally invasive resection of mediastinal tumors.