Stop is overall a dance-pop and europop track. The first verse consists of a line for each of the girls to sing. The song then progresses on to the refrain with lyrics sung by Victoria and Melanie B. The chorus is next after that sung by all members but ends with Melanie C's line in the chorus. The next verse is sung by Emma and Melanie C. Then the refrain and chorus are repeated. A interlude is introduced with "Ba da da da, ba da da da..." The bridge is introduced thereafter with a quicker pace of lyrics than the previous parts of the lyrics. The chorus is then repeated three times after, with Melanie C doing backing vocals.
The chords for the verses consists of C-Bb-Am-G which is repeated to the end. The refrains consist of Dm-Dm-Dm-Em-F-G. The choruses chords are the same to that of the verses.
The song is reminiscent of The Supremes single Stop! In the Name of Love (released in 1965) and other classic girl group songs.