Ryan had been floating a potential bid as some House Democrats pushed for leadership changes following a rough election for Democrats across the country.
The Ohio congressman told CNN earlier Thursday that it is "the definition of insanity" for Democrats to do "same thing over and over again and keep getting the same results."
Democrats announced on Tuesday that they would delay leadership elections until after Thanksgiving as Ryan began floating his bid for leader. Some Democrats also reportedly urged Rep. Joe Crowley (D-NY) to challenge Pelosi for the top spot leading the caucus. Though there have been grumblings in the Democratic caucus about the need for change in leadership, Ryan's bid against Pelosi is a long shot.
When asked about a potential challenge on Thursday, Pelosi told reporters that two thirds of the House Democratic caucus have backed her re-election.