Influenza, followed by severe acute bacterial pneumonia, is a major cause of mortality worldwide. Several mechanisms account for this enhanced susceptibility, including increased production of Type I IFN. In individuals infected with Mycobacterium tuberculosis, the influence of acute viral infections on tuberculosis progression is unclear. We show that prior exposure of mice to influenza A, followed by M. tuberculosis infection, leads to enhanced mycobacterial growth and decreased survival. Following M. tuberculosis/influenza co-infection, mycobacterial growth is enhanced by a Type I IFN signalling pathway. Our findings highlight the detrimental impact influenza infection can have prior to, or during M. tuberculosis infection.