The actress is "in talks" to reprise her role, according to The Hollywood Reporter, while Deadline said MGM is "near a deal" with the star.
Witherspoon made her name as the irrepressible law student in the 2001 film, and starred in the 2003 sequel.
The sequel ended with Elle setting her sights on the White House.
There are no details yet about the plot of Legally Blonde 3 and what might have become of Elle during the last 15 years.
But fans will be eager to see who she's got in her sights in the age of Donald Trump and Me Too.
