BACKGROUND: Alterations in corticospinal excitability (CSE) to the quadriceps persist after anterior cruciate ligament reconstruction (ACLR). Centrally targeted interventions, such as transcranial direct current stimulation (tDCS), may be necessary to increase CSE and quadriceps muscle strength. The purpose of this study was to determine (I) the feasibility and safety of a single session of tDCS and (II) the effects of a single session of tDCS on CSE and quadriceps muscle performance in participants after ACLR. METHODS: This was a randomized crossover design of a single session of active RESULTS: There were no adverse events reported and no participant drop out. There was no significant condition by time interactions for CSE (P≥0.17) or quadriceps performance (P≥0.53). There was a significant main effect of time for RTD200 (P=0.02) with decreased RTD200 post-intervention regardless of condition. CONCLUSIONS: TDCS is safe and feasible for participants recovering from ACLR. There were no acute effects of a single session of a-tDCS on CSE and quadriceps performance measures. Multiple sessions of tDCS and/or tDCS during other tasks (e.g., during isolated quadriceps exercises) may lead to improved CSE and quadriceps performance. TRIAL REGISTRATION: ClinicalTrials.gov ID: NCT04504344.