A method for monitoring an ignition system including a spark plug of an internal combustion engine is disclosed. The method comprises determining an operation value associated with an electrical parameter indicative of an operation of the ignition system during actuation of the spark plug. The method further comprises determining at least one parameter indicative of a current engine operation condition of the internal combustion engine, and determining a current spark plug state of the spark plug based on the at least one engine parameter and the operation value associated with the electrical parameter of the ignition system.