Glycosyl-inositols are molecules consisting of one or more α- or β-D-glycosyl residues bonded primarily to inositol or methyl-inositol. These derivatives are found in plants, yeast, bacteria, and parasites, and exhibit diverse biological properties. The limited availability of glycosyl inositols from natural sources has led to significant interest in chemical and enzymatic synthesis techniques due to their potential applications in various fields. This review provides a comprehensive overview of inositols, methyl-inositols, and primarily glycosyl inositols, focusing on their classification, natural occurrence, biological roles, and potential applications across different disciplines. Inositols, particularly myo-inositol and its derivatives are widely distributed in plants and play essential roles in biochemical processes and metabolic functions in different organs and tissues. Glycosyl inositols, including glycosylphosphatidylinositols, glycosyl inositol phosphorylceramides, phosphatidylinositol mannosides, monoglycosyl and diglycosyl derivatives, are discussed, emphasizing their structural diversity and biological functions. Methods for their chemical and enzymatic synthesis are also reviewed, highlighting recent advances and challenges in the field. Overall, this comprehensive review underscores the significance of glycosyl inositols as versatile molecules with diverse biological functions and promising applications in scientific research and industry.