Galectin-3 (Gal-3), a member of the beta-galactoside-binding gene family, distributes inside and outside the cell and has pleiotropic biological functions such as cell growth, cell adhesion, cell-cell interaction, and mRNA processing in a specific situation. In particular, Gal-3 in the nucleus plays a pivotal role in the regulation of cancer-related gene expression, including cyclin D1, TTF-1 and MUC2, presumably associated with tumor progression. Therefore, to understand the mechanism of nuclear import of Gal-3 is very significant and might be developed to the new approach for the cancer treatment. In this review, we focus on the role of Gal-3 in the nucleus and the molecular mechanism of nuclear import pathways of Gal-3, providing the hints for the inhibition of Gal-3 function.