"Irresistible" was received with mostly mixed reviews by music critics. Although a few critics called the song a "peppy" number, others commented that they did not like the song, and criticized the sexuality of its lyrics and the over-usage of digital sound manipulators. Stephen Thomas Erlewine of Allmusic stated that the song and "A Little Bit", the second single released from the parent album, were a "double-punch" and picked the former song as a standout from the album. "Cashbox Canada", ranking the song at number ten on "Top 10 Love Songs: The Crush", praised it as "an ode to love at step one". Similarly, Chuck Taylor of "Billboard" reviewed "Irresistible" favorably, calling it "a sexy, uptempo romp about new found love that proves Simpson's pop intuition." In another review, Taylor complimented the contemporary appeal of the track and felt that it would be a staple at radios. He also noticed that the breakdown and spoken passages of the song gave it a "street edge", something not previously heard from Simpson. Teresa Gubbins of "The Dallas Morning News" had mixed feelings towards the song in her review, writing that its sound might help Simpson get attention on urban radios, but did nothing to demonstrate her voice. Larry Printz of "The Morning Call" also expressed a similar view of the song, stating that the song "is loaded with platitudes, but [it's] easy on the ears."