The 1905 AAA National Motor Car Championship consisted of 11 points-paying races, beginning in The Bronx, New York on June 10 and concluding in Poughkeepsie, New York on September 29.

This was the first year that the AAA Contest Board (then known as the Racing Board) officially recognized a National Champion in American Championship Car competition.

For reasons unclear, but likely due to a change in attitudes and opinions by AAA officials about the dangers of racing following several serious accidents, no national championship was officially recognized again until 1916.

In 1951, Victor Hémery, winner of the 1905 Vanderbilt Cup, was retroactively awarded a national championship.

At a later point, it was recognized by historians that these championship results were revisionist, after discovering published sources naming Oldfield as the National Champion.