Abstract: The present invention relates to a lens system for a head-up display. The technical gist of the present invention is to provide a lens system for a head-up display, comprising: a first group of lenses positioned toward a screen with reference to a diaphragm; and a second group of lenses positioned toward an image element, wherein each lens is combined/arranged such that the DN/DT (abs.) (temperature coefficients of refractive index (10?6/° C. at 632.8 nm)) value of a lens that satisfies |P|>=40 (P is refractive power of each lens), among the plurality of lenses constituting the first and second groups of lenses, has a positive number value or a negative number value according to the refractive power, and the lens system accordingly has thermal compensation characteristics by controlling the amount of change in the focal distance of each lens.