"That's Why" can refer to the following:
That's Why (album), a 2008 album by Craig Morgan, and the title song "That's Why", a 1991 single by The Party, from the album The Party "That's Why", a 2019 song by Illenium, from the album Ascend "That's Why", a 1982 song by Michael McDonald, from the album If That's What It Takes "That's Why (I Love You So)", a 1959 single by Jackie Wilson "That's Why (You Go Away)", a 1995 single by Danish band Michael Learns to Rock
See also "That Is Why", a 1990 single by the band Jellyfish