Interleukin‐17 (IL‐17) is a multifaceted cytokine with diverse roles in both immune protection and also immunopathology. IL‐17 has a well‐recognized role in immune surveillance at mucosal and barrier surfaces, but also has been increasingly implicated as a driver of immunopathology in settings of autoimmunity and chronic inflammation. The current review introduces basic aspects of IL‐17 biology and examines the protective and pathogenic roles of IL‐17 with a focus on oral mucosal immunity and inflammation. Specific emphasis is given to the role of the IL‐17 response as a catalyst in ‘shaping the microbiome at the oral barrier’.