The solute carrier family 35 (SLC35) comprises multiple members of transporters, including a group of proteins known as nucleotide sugar transporters (NSTs), an adenosine triphosphate (ATP) transporter, 3′-phosphoadenosine 5′-phosphosulfate (PAPS) transporters, and transporters of unknown function. To date, seven subfamilies (A to G) and 32 members have been classified into this large SLC35 family. Since the majority of glycosylation reactions occur within the lumen of the endoplasmic reticulum (ER) and Golgi apparatus, the functions of NSTs are indispensable for the delivery of substrates for glycosylation. Recent studies have revealed the diverse functions of this family of proteins in the regulation of numerous biological processes, including development, differentiation, proliferation, and disease progression. Furthermore, several congenital disorders of glycosylation (CDGs) resulting from variations in the SLC35 family member genes have been identified. To elucidate the pathology of these diseases, a variety of knockout mice harboring mutations in the family member genes have been generated and employed as animal models for CDGs. This review presents a historical overview of the SLC35 family, with a particular focus on recent advances in research on the functions of this family and their relationship to human diseases.