An air-fuel ratio control apparatus is applied to an internal combustion engine including a variable lift mechanism which changes a lift amount of an intake valve. An oxygen sensor, which outputs a signal indicating an oxygen concentration in exhaust gas, is provided downstream of an exhaust gas purification catalyst in an exhaust passage of the internal combustion engine. Air-fuel ratio control is performed to correct the fuel injection amount command value using the correction amount that is set based on the value output from the oxygen sensor. The relationship among the deviation of the correction amount from its reference value, the learned small lift value, the learned medium lift value, and the lift amount is learned. The learned deviation value is calculated based on the lift amount, using the learned relationship. Then, the fuel injection amount command value is corrected by the correction amount including the calculated learned deviation value.