Summary: Self-excited combustion oscillations arise from a coupling between unsteady combustion and acoustic waves, and can cause structural damage to many combustion systems. Active control provides a way of extending the systems' stable operating range by interrupting the damaging thermoacoustic interaction. The active controller considered injects some fuel unsteadily into the burning region, thereby altering the heat-release rate, in response to an input signal detecting the oscillation. Although the feasibility of such a control configuration was demonstrated on laboratory-scale experiments over 15 years ago, the triple requirement for full-scale applications is to adapt the controller response to varying operating conditions and to guarantee that the controller will cause no harm, while relying as little as possible on a particular combustion model. As a first step towards meeting these requirements, a self-tuning regulator (STR) is proposed in this paper for a class of combustion systems that satisfy some fairly non-restrictive assumptions. An open-loop transfer function from the controller output voltage driving the actuator to the pressure signal detecting the oscillation is derived, and is shown to be the product of a time delay \(\tau_{\text{tot}}\) and a transfer function that satisfies certain structural properties. Using the open-loop transfer function, it is shown that the stabilizing STR structure is that of a simple phase-lead compensator if \(\tau_{\text{tot}} = 0\), and the same compensator combined with a Smith controller if \(\tau_{\text{tot}}\neq 0\). The adaptive rule for the adjustment of the STR parameters is derived from a Lyapunov stability analysis. Promising results are obtained on a simulation based on a nonlinear premixed flame model and on an experimental set-up which consists of a laminar flame burning in a Rijke tube.