In a statement issued to staff, NBC News chairman Andrew Lack explained that network execs had received a complaint against Lauer, and following "serious review," found the Today star to have violated the company's standards.
The memo continued: "While it is the first complaint about his behaviour in the over 20 years he's been at NBC News, we were also presented with reason to believe this may not have been an isolated incident."
This morning's program opened with a subdued introduction from Lauer's former co-stars Savannah Guthrie and Hoda Kotb.
"As I'm sure you can imagine, we are devastated and we are still processing all of this," Guthrie said on-air. "I will tell you right now we do not know more than what I just shared with you, but we will be covering this story as reporters, as journalists. I'm sure we will be learning more details in the hours and days to come. And we promise we will share that with you."
Watch a segment from today's (November 29) episode below.
Matt Lauer has been terminated from NBC News. On Monday night, we received a detailed complaint from a colleague about inappropriate sexual behavior in the workplace by Matt Lauer. As a result, we've decided to terminate his employment. pic.twitter.com/1A3UAZpvPb— TODAY (@TODAYshow) November 29, 2017
Lauer began his tenure on Today back in 1994, eventually becoming a co-anchor in 1998.
He is the latest television personality to lose his job in the wake of sexual misconduct allegations. Earlier this month, PBS and CBS presenter Charlie Rose was fired and removed from the air.