Sources told TMZ the 18-year-old reality star and 26-year-old rapper split prior to the Met gala, where they walked the red carpet separately. An insider said the breakup was "acrimonious," with no reconciliation in sight.
"They fight and get back together all in the same day constantly ... that's how it always is," a source added to Us Weekly. Another insider told the magazine the pair "are not speaking right now."
Jenner and Tyga went public with their relationship at the reality star's 18th birthday party in August. The couple were previously rumored to have split in November, but Jenner denied a breakup the same month.
"Honestly, people have it all wrong," she said at the time. "We're not broken up. We became best friends before anything happened, so I think that's awesome. We're just hanging out. We're still together."
A source told E! News the split was "a long time coming," with another insider citing the pair's "complicated" relationship. Jenner's half-brother Rob Kardashian announced he's expecting with Tyga's ex-fianceé, Blac Chyna, days after the Met gala.
"[Rob's sisters] were super shocked at first about the pregnancy news, especially Kylie," a source told People. "Kylie was especially pushed to swallow her pride and support her family, even if she didn't want to."
Jenner and Tyga have yet to address their reported split. The reality star appears on her family's E! series, Keeping Up with the Kardashians, and will release a swimwear line with sister Kendall Jenner for Topshop.