Triple-negative breast cancer (TNBC) is highly aggressive and lacks targeted therapies. This study investigated the anti-cancer mechanisms of sinapaldehyde (SNAH). The biological effects of SNAH were evaluated in vitro using MDA-MB-231 TNBC cells. Cellular responses, including autophagy, mitochondrial function, apoptosis, cell-cycle progression, migration, and colony formation were investigated. In silico studies explored associated regulatory networks and binding targets. Sinapaldehyde (SNAH) treatment was associated with mitochondrial dysfunction, characterized by alterations in mitochondrial structural and functional markers, increased reactive oxygen species(ROS) production, and loss of mitochondrial membrane potential. SNAH treatment also altered the expression of PINK1 and Parkin and modulated autophagy-associated markers, including LC3B, p62, LAMP1, Beclin-1, and ATG proteins. Time-dependent changes in autophagy- and apoptosis-associated markers were accompanied by increased Annexin V-positive cells and activation of cleaved caspase-9 and caspase-3. SNAH also altered FTH1 and NCOA4 expression, suggesting modulation of ferritinophagy-associated processes, and inhibited migration and colony formation while inducing G2/M cell-cycle arrest. In silico analyses identified potential breast cancer-related molecular targets and signaling pathways associated with SNAH. SNAH induces mitochondrial dysfunction and is associated with alterations in autophagy/mitophagy-associated signaling and activation of apoptosis in MDA-MB-231 TNBC cells. These findings provide insight into the cellular responses to SNAH treatment, while further functional studies are required to establish changes in mitophagic and ferritinophagic flux and the causal relationship between autophagy and apoptosis.