Black Sabbath bassist Geezer Butler (from Guitar World magazine, March 2004): A lot of the Paranoid album was written around the time of our first album, Black Sabbath.

We basically needed a 3 minute filler for the album, and Tony came up with the riff.

Originally, the band had wanted to call the album War Pigs after the song of the same name, but the record company persuaded them to use "Paranoid" instead because it was less offensive.

[9] Cash Box described the song as being "as dense, musically as 'Whole Lotta Love,'" stating that "crashing, non-stop beat with gobs of bass and drums laced liberally with stinging, echoey vocals and hot guitar licks move the song along at a blistering pace.

"[13] "Paranoid" was ranked the fifth best Black Sabbath song by Rock – Das Gesamtwerk der größten Rock-Acts im Check.