Temperature sensitive sol-gel transition polymers, termed as thermogels, are aqueous polymer solutions that undergo solution-to-gel transition as the temperature increases. Typically, it is in a sol state at room temperature, however, it turns into hydrogel at physiological temperature of 37 oC. Poly(lactic acid-co-glycolic acid), Pluronic derivatives, polycaprolactone, polytrimethylene carbonate, and polypeptides have been developed as thermogels by balancing hydrophilicity and hydrophobicity for injectable drug delivery and tissue engineering applications. In particular, polypeptide thermogels are intensively being investigated for the last decade for maintaining neutral pH during degradation and storage stability under in vitro condition while in vivo degradability by enzymes. Cells, growth factors, and signaling molecules were simultaneously incorporated into the gel during the sol-to-gel transition, thus providing an excellent platform for 3D culture of stem cells.