The couple, who were known colloquially as "Kete", had been dating for nine months, after meeting on the set of Saturday Night Live, the comedy sketch show on which Davidson was a cast member.
E! News was the first to report the end of their romance, citing sources who claimed the pair's busy schedules was to blame for the break-up.
They still have "a lot of love and respect for each other" but found that the long distance dynamic and their demanding schedules "made it really difficult to maintain a relationship", the E! News sources said. The split occurred sometime this week.
Kardashian, 41, was in the midst of legal proceedings to finalise her divorce from rapper Kanye West when she met Davidson, 28. Their relationship attracted the ire of West, who made a string of online attacks against Davidson.
Kardashian and West married in 2014 and share four children: North, 9; Saint, 6; Chicago, 4; and Psalm, who is 3.
Kardashian was declared legally single in March.
The whirlwind Kardashian-Davidson relationship attracted headlines with the couple making their first public appearance together at the White House Correspondents' Dinner in April.
Davidson even made a cameo on the Hulu reality show The Kardashians and is expected to appear on the second season screening later this year. The comedian also reportedly has a tattoo celebrating their relationship.
The ink on his collarbone has the names "Jasmine" and "Aladdin" with an infinity sign in the middle, according to E! News. Kardashian and Davidson played the beloved characters on Saturday Night Live where they first met.
Davidson was a cast member on the hit show for eight seasons before announcing his departure in May. He has recently been filming a movie called Wizards! in Australia.