When "The Substitute" was first broadcast on FOX, it was watched by 11.70 million US viewers. It had a 5.0/14 Neilsen rating/share in the 18-49 demographic group. This helped the episode to become the top-rated program of the night for adults aged 18–49. In the weekly rankings, the episode was the top scripted program for adults 18-49. Overall, it placed twentieth for the second season. Views and ratings were both better than the previous episode, "Never Been Kissed". It was watched by 10.99 million viewers and had a 4.6/13 rating/share. In Canada, viewership was also better than the last episode. It was watched by 2.29 million viewers and ranked ninth for the week. The last episode had 1.97 million viewers and ranked twelfth. In Australia, the episode was watched by 1.06 million viewers. This made "Glee" the seventh most-watched program of the night and nineteenth of the week. In the UK, the episode was watched by 2.55 million viewers-2.11 million on E4, and 439,000 on E4+1. It was the most-watched show on cable for that week.