A wavelength conversion element is provided. The wavelength conversion element includes a substrate, a wavelength conversion layer, a reflective layer, and a heat conductive layer. The wavelength conversion layer is disposed on the substrate. The reflective layer is disposed on the substrate and is located between the substrate and the wavelength conversion layer. The heat conductive layer is disposed on the substrate, and at least a portion of the heat conductive layer is located between the substrate and the reflective layer. A projector is also provided, and the projector includes the wavelength conversion element. The wavelength conversion element exhibits a favorable heat dissipation effect and provides improved conversion efficiency, so that the projector exhibits favorable projection quality and product competitiveness.