The World Health Organization (WHO) has added glass ionomer cement (GIC) to the WHO Model List of Essential Medicines since 2021, which represents the most efficacious, safe and cost-effective medicines for priority conditions. With the potential increase in the use of GIC, this review aims to provide an overview of the clinical application of GIC with updated evidence in restorative and preventive dentistry. GIC is a versatile dental material that has a wide range of clinical applications, particularly in restorative and preventive dentistry. It has unique properties, such as direct adhesion to tooth structures, minimal shrinkage or expansion, a similar coefficient of thermal expansion to natural tooth structure, biocompatibility, and long-lasting fluoride release. According to the chemical composition, GIC can be classified as conventional glass ionomer cement (CGIC) and resin-modified glass ionomer cement (RMGIC). It has been used as restorative materials, luting cement for indirect restorations, liner and base of restorations, and dental sealants. While its use as a base material and liner is debatable, the clinical application of GIC as restorative cement, luting cement, and dental sealant is supported by current research.