Emerin (EMD) plays diverse roles in cellular polarity organization, nuclear stability, and cell motility, however, the biological role of EMD relevant to the migration and invasion of hepatocellular carcinoma (HCC) cells has not yet been illustrated. In the present study, we initially found that the upregulation of EMD in HCC tissues, and EMD expression was negatively correlated with the spontaneous metastatic potential of HCC cell lines. Loss of EMD in HCC cells facilitated cell migration and invasion in vitro and metastasis in vivo. Meanwhile, we demonstrated that EMD knockdown induced EMT but enhanced p21 expression in HCC cells. Notably, silencing of EMD in HCC cells increased the cytoplasmic localization of p21 protein, whereas p21 knockdown partially abrogated the migratory and invasive ability, EMT, and the actin cytoskeleton rearrangement induced by EMD knockdown in HCC cells. Our results indicated a significant role of EMD knockdown in the HCC cell motility and metastasis through upregulating the cytoplasmic p21, unveiling a novel mechanism of cell motility regulation induced by EMD.