Background/Objectives: Oral squamous cell carcinoma (OSCC) is a significant global health concern, necessitating the development of novel treatment strategies. The present study investigated the in vitro anticancer activity of sulforaphane (SFN), an isothiocyanate derived from Brassica oleracea, on the OECM-1 human oral squamous carcinoma cell line. Methods: OECM-1 cells were cultured and exposed to a range of SFN concentrations. To assess the cell viability and determine the half maximal inhibitory concentration (IC50) of SFN following 24 h of treatment, an MTT assay was performed. Apoptosis was evaluated using AO/PI staining, a TUNEL assay, Annexin V-FITC analysis, and a DNA fragmentation assay. Changes in the mitochondrial membrane potential were analyzed using a JC-1 staining assay. A Western blot assay was performed to assess the expression levels of apoptosis-associated proteins (Bax, Bcl2, caspase-3, caspase-9, PARP, Smad-4, p53, cytochrome c, and GAPDH). Cell cycle analysis was performed to validate the apoptotic findings. Results: The IC50 concentration of SFN was 5.7 µM. The apoptotic assays demonstrated an effective induction of apoptosis in the OECM-1 cells. Western blot analysis demonstrated the dose-dependent upregulation of p53, caspase-3, caspase-9, PARP, cytochrome c, and Bax and the downregulation of the anti-apoptotic proteins Bcl-2 and Smad-4 after SFN treatment. Conclusions: The data obtained indicate that SFN has significant potential to induce apoptosis in OECM-1 cells by disrupting mitochondrial function and modulating apoptotic pathways. The outcomes of our research indicate SFN's potential as a viable treatment drug for OSCC.