Oral cancer is a malignancy with unfavorable prognosis due to its high rates of recurrence and lymph node metastasis. Narciclasine is extracted from Narcissus species (Amaryllidaceae), which have antitumor and anti-inflammatory properties. However, the antitumor properties of narciclasine toward oral cancer remain unclear. The present study explored the antimetastatic effects of narciclasine in oral cancer as well as the underlying molecular mechanisms. We treated three oral cancer cell lines with noncytotoxic concentrations of narciclasine and discovered a dose-dependent antimetastatic effect. Mitogen-activated protein kinase (MAPK) pathways, including extracellular signal–related kinase (ERK), p38, and c-Jun N-terminal kinase (JNK), were regulated by narciclasine. We further discovered the ERK pathway to directly affect narciclasine-induced metastasis inhibition by combining treatment with narciclasine and ERK inhibitor. Furthermore, downregulation of cathepsin B (CTSB) in the SAS and SCC-47 cell lines revealed the critical role of CTSB in the antimetastatic effect of narciclasine. Our findings indicate that narciclasine inhibits oral cancer metastasis by regulating the ERK pathway and CTSB. This study provides evidence of the mechanism of narciclasine-induced inhibition oral cancer metastasis and suggests potential targets for use in oral cancer treatment.