A work vehicle including: a vehicle body frame; a prime mover part located on a front or rear part of the vehicle body frame; a bonnet configured to open and close by swinging, and covering the prime mover part; and an assist unit configured to assist the bonnet to operate to open. A lateral end portion of the vehicle body frame is provided with a first linkage part with which the assist unit is linked. A lateral end portion of a lower end part of the bonnet, which is located closer to an end cover than the first linkage part is, is provided with a second linkage part with which the assist unit is linked. The assist unit is provided with an expansion/contraction mechanism biased so as to expand, and is located laterally outside the prime mover part and spans the first linkage part and the second linkage part.