A panel assembly for a vehicle made of different materials with different coefficients of thermal expansion according to various exemplary embodiments of the present invention includes: an external panel 10, an internal panel 20 having the circumference bonded to the circumference of the external panel 10, and made of a material having a coefficient of thermal expansion different from a coefficient of thermal expansion of the external panel 10, and at least one deformation absorption panel 30, 40 connected to at least one of the external panel 10 and the internal panel 20 on the circumferences of the external panel 10 and the internal panel 20, and for absorbing an amount of thermal deformation according to a change in temperatures of the external panel 10 and the internal panel 20 when the external panel 10 and the internal panel 20 are thermally deformed.