Coxiella burnetii is an obligate intracellular bacterial pathogen that causes the zoonosis Q fever. While an effective whole-cell vaccine (WCV) against Q fever exists, the vaccine has limitations in being highly reactogenic in sensitized individuals. Thus, a safe and effective vaccine based on recombinant protein antigen (Ag) is desirable. To achieve this goal, a better understanding of the host response to primary infection and the precise mechanisms involved in protective immunity to C. burnetii are needed. This review summarizes our current understanding of adaptive immunity to C. burnetii with a focus on recent developments in the field.