Nicholas Fonseca from Entertainment Weekly considered the track a "tween-slumber-party-friendly" which "is perfect for singing into your curling iron in front of the mirror".
John Murphy of MusicOMH cited "Over" as being "actually rather good" and noted similarities between the song and the works of Michelle Branch.
Lyrically, "Over" is about how her boyfriend will not commit and that their relationship feels "on again, off again".
Recorded and mixed at Henson Recording Studios.
"Over" is written in the time signature of common time with a moderate tempo of 90 beats per minute.