The song received acclaim from music critics, with many claiming it defied teen pop expectations and was Breakout's best track.

The song's lyrics, written by Cyrus, Antonina Armato, Tim James and Devrim Karaoglu, have been mistakenly interpreted in a variety of ways.

[2] Ben Ratliff of The New York Times sided with the boyfriend, and believed the song's protagonist was "bullying some poor boy for the sin of wanting to know what she talks about with her friends".

[3] Sarah Rodman of The Boston Globe believed the song could have described a number of subjects, such as "a former boyfriend, the media, and even her fans".

[2] Sarah Rodman of The Boston Globe said "Fly on the Wall" was a change of pace for Cyrus and called it "the album's most interesting tune".

[4] Mikael Wood of the Los Angeles Times said the song is a result of regular Walt Disney Company standards, yet "the CD's best cut".

[10] Johnny Dee of Virgin Media said the song and "7 Things" were "feisty pop belters" that would encourage a long-term career.

[11] Ratliff negatively compared "Fly on the Wall" to the Pussycat Dolls and said that although Cyrus' voice is generally rich with a deep range, it became "pinched and stingy" in the single.

[14] In the Canadian Hot 100, the peaked and debuted at number 73 on the week ending August 9, 2008, due to digital downloads.

[18][19][20] For the week ending February 28, the song ascended to number 16 and became Cyrus' second best charting single in the United Kingdom at the time.

In an interview with MTV News, director Philip Andelman explained that Cyrus was already determined to poke fun at the paparazzi when she contacted him for a "Fly on the Wall" music video.

It then focuses on Cyrus, wearing a white tank top, jeans, boots and a black leather jacket, and her boyfriend leaving a theater and discussing the film they saw.

The music of "Fly on the Wall" begins as Cyrus runs into a parking garage and tries to hide behind a pillar and a black Mercedes-Benz SLR McLaren.

Clips interspaced throughout the video feature her in a long silver shirt and jeans singing and dancing in front of the Mercedes.

MTV also compared the "Fly on the Wall" video to those for Britney Spears' "Circus" and Lindsay Lohan's "Rumors".

[31] On July 18, 2008, the song was performed in a concert series for Good Morning America along with "Breakout", "7 Things" and "Bottom of the Ocean".

[34] A critic from ABC stated that Cyrus "fearlessly embraced new creative directions" with her performance of "Fly on the Wall".

[37][38] For the event, she had an abundance of background dancers, and Cyrus wore a casual patterned gray T-shirt, black pants, and boots.

[42] On June 7, 2009, at the twentieth annual A Time for Heroes Celebrity Carnival, Cyrus performed "Fly on the Wall".

The performance began with two overhead screens displaying a frog catching a fly while two acrobats scaled imaginary walls.

[46] At the conclusion, Cyrus and her background dancers grouped together to perform a segment of the dance from Michael Jackson's "Thriller" music video.