Abstract Nontypeable Haemophilus influenzae(NTHi) is one of the most common bacteria that cause secondary bacterial pneumonia following influenza A virus (IAV) infection, leading to hospitalization and death associated with IAV infection worldwide. Current efforts to develop vaccines against NTHi infection focus on inducing antibodies but are hindered by antigenic diversity among NTHi strains. Therefore, we interrogated the contribution of the memory T-helper type 17 (T H17) response in protective immunity against IAV/NTHi co-infection. We observed that co-infected mice exhibited prolonged NTHi infection in the lungs even at mild IAV infection and impaired NTHi-specific T H17 responses compared to NTHi mono-infected mice. However, immune mice that recovered from a prior NTHi infection were protected from homologous and heterologous secondary NTHi strains following IAV infection. Our data further revealed that memory NTHi-specific T H17 cells overcame IAV-driven impairments of anti-NTHi T H17 responses and were cross-reactive with different NTHi strains. Last, mice immunized with a NTHi protein that induced a strong T H17 memory response were broadly protected against diverse NTHi strains following challenge with IAV/NTHi co-infection. These results indicate that NTHi-specific memory T H17 cells are capable of providing serotype-independent protection against co-infection and demonstrate the advantage of developing broadly protective T H17-inducing vaccines against secondary bacterial pneumonia.