We report the discovery of MASCARA-3b, a hot Jupiter orbiting its bright (V=8.33) late F-type host every 5.55149+/-0.00001-days in an almost circular orbit (e=0.050^+0.020^_-0.017_). This is the fourth exoplanet discovered with the Multi-site All-Sky CAmeRA (MASCARA), and the first of these that orbits a late-type star. Follow-up spectroscopic measurements were obtained in and out of transit with the Hertzsprung SONG telescope. Combining the MASCARA photometry and SONG radial velocities reveals a radius and mass of 1.36+/-0.05R_Jup_ and 4.2+/-0.2M_Jup_. In addition, SONG spectroscopic transit observations were obtained on two separate nights. From analyzing the mean out-of-transit broadening function, we obtain vsini*=20.4+/-0.4km/s. In addition, investigating the Rossiter-McLaughlin effect, as observed in the distortion of the stellar lines directly and through velocity anoma lies, we find the projected obliquity to be {lambda}=1.2^+8.2^_-7.4_deg, which is consistent with alignment.