The invention discloses a projector, including a light source, a light engine module and a lens module. The lens module includes a plate, a lens, at least two sliding components and a first position adjustment device. The sliding components are disposed between the plate and a light engine housing and located respectively at a first position and a second position of the light engine housing. Each of the sliding components has a sliding member and a distance adjustment member. The plate is movably disposed on the light engine housing via the sliding member. The distance adjustment members are in contact with the sliding members respectively. The first position adjustment device is movably disposed between the plate and the light engine housing. The invention further discloses a lens module. The invention can improve movement accuracy and imaging stability of a projector and a lens module.