A simple percussion that is consistent throughout does not dominate but simply backs the moderate tempo of the song. However, the changing progressions and phrasing throughout the song gives the illusion of a changing tempo and time signature. The instrumentation is built on top of a bass line that is an "Oom pah" sound reminiscent of a military march or civic band. In the first half of the song, this is accompanied with a strummed acoustic guitar that compliments the percussion. In the last verse, Harrison introduces a picked instrument, probably a 12 string guitar, that plays counter melody and gives the song a Mediterranean or Eastern sound not unlike the sitar used in later works.
"Girl", like many of the songs on the album, was mixed with all the vocals on one channel and the instruments on the other. This was a move toward greater use and experimentation in the studio. Many of the elements of "Girl" would be expanded on and would show up on their subsequent recordings.