Background: Sarcomatoid squamous cell carcinoma (SCC) is a rare and biologically aggressive variant of oral cavity SCC, with limited comparative survival data versus conventional SCC. This study evaluated clinicopathological features and survival outcomes of sarcomatoid oral SCC and compared disease-free survival (DFS) and overall survival (OS) with conventional oral SCC. Methods: In this retrospective cohort study, surgically treated patients with oral cavity SCC managed between January 2020 and December 2024 were analyzed. Sixty-four patients with sarcomatoid SCC identified from a prospectively maintained database were compared with 152 patients with conventional oral SCC selected by computer-based random sampling. Survival outcomes were assessed using Kaplan–Meier analysis and log-rank testing. Cox proportional hazards regression identified factors associated with DFS and OS. Results: Baseline demographic characteristics and major pathological risk factors were comparable between cohorts. At a median follow-up of 22 months, 1-year and 3-year OS rates were significantly lower in sarcomatoid SCC (66.8% and 47.9%) compared with conventional SCC (91.9% and 75.2%; p<0.001). Similarly, DFS was inferior in sarcomatoid SCC at both 1 year (63–65%) and 3 years (30–35%) versus conventional SCC (86–87% and 66–70%; p<0.001). On multivariate analysis, sarcomatoid histology independently predicted poorer DFS (HR 3.79; p<0.001) and OS (HR 3.09; p<0.001). Conclusions: Sarcomatoid histology confers a significantly adverse prognosis independent of stage and established risk factors, supporting its classification as a distinct high-risk biological subtype.