The current review focuses on intracellular and extracellular roles that Gal-3 plays in controlling phagocytosis and macropinocytosis; phagocytosis in professional phagocytes (e.g., microglia and macrophages) and non-professional phagocytes (e.g., Schwann cells and astrocytes); and macropinocytosis in some types of cancer cells. Here, LGALS3 is linked to cancer.