A curable composition and use thereof are provided. The composition can be useful in exhibiting excellent processability and workability, and providing a cured product which exhibits superior light extraction efficiency, crack resistance, hardness, thermal shock resistance, and adhesive properties, has superior reliability under severe conditions for a long period of time and prevents opacity and stickiness onto a surface thereof when cured. Also, the curable composition capable of preventing precipitation of an additive such as a fluorescent material or a photoconversion material and being formed into a cured product having excellent transparency even when the additive is added to the curable composition can be provided.