[6] Mojo magazine cited the lyrics as presenting an alternate view of the American Dream to that described in another song from the Boston album, "Hitch a Ride".

[11] The Greenwood Encyclopedia of Rock History described the song as being "built around soaring guitars, tight vocal harmonies, and huge hooks," which were part of the band's appeal.

[12] Boston lead singer Brad Delp cited "Peace of Mind" as an example of how Scholz was able to combine the vocal harmonies of the Beach Boys with the heavy guitar sound of Led Zeppelin.

Cash Box said "this might be [Boston's] best yet as far as all pop radio stations are concerned, since the record maintains an acoustical feeling despite the electronic thunderbolts crashing in the distance.

"[17] Rolling Stone Album Guide critic Paul Evans called "Peace of Mind" a "satisfying, if similar, followup" to "More Than a Feeling".

[18] Scott Tady of Beaver County Times described "Peace of Mind" as one of the songs that "helped set the foundation for classic-rock radio".

[19] Eric Deggans wrote that "Bouncy, slick tracks such as "More Than a Feeling" and "Peace of Mind" defined new parameters for rock radio during the 70s, with soaring vocals searing guitars and trite lyrics.

"[23] Gallucci rated it Boston's fifth greatest song, particularly praising the "fuzzy guitar riff" and noting that it has remained a classic rock radio staple.