Past studies utilizing cognitive control tasks have noted that trials following errors are characterized by slowed reaction time. Despite the assumption long held by researchers that this slowing is compensatory (in the service of post‐error performance recovery), studies consistently show that post‐error trials are no more accurate than post‐correct trials. As a result, it has recently been proposed that post‐error slowing (PES) is merely part of an orienting response that serves no task‐relevant cognitive control purpose. Frontal midline theta (FMθ) oscillations represent another potential compensatory mechanism serving cognitive control processes, yet past studies relying on ERPs have failed to find an association between FMθ and post‐error accuracy. The present study investigated the potentially adaptive role of PES and FMθ oscillations during a flanker task using trial‐by‐trial comparisons. Results indicated that error‐related FMθ oscillations signal the need for enhanced top‐down cognitive control and that PES supports cognitive control by providing the added time needed to achieve greater confidence in judgment. Overall, findings provide convergent evidence that both error‐related FMθ and PES predict performance recovery following errors.