Yeast and silkworms are emerging as practical alternative hosts for glycoprotein production, complementing mammalian cell-based systems. Advances in glycoengineering have enabled precise modification of endogenous glycosylation pathways, allowing the synthesis of human-compatible N-glycans. In yeast, disruption of native glycosylation genes and introduction of mammalian glycosyltransferases support the production of high-mannose, hybrid, complex, and mannose-6-phosphate glycans. In silkworms, suppression of β-N-acetylglucosaminidase activity and co-expression of mammalian enzymes enable conversion of paucimannose-type glycans to complextypes, including fucosylated structures. These technologies expand the applicability of yeast and silkworms for costeffective biopharmaceutical manufacturing, while highlighting remaining challenges in glycan control and quality evaluation.