Pelosi, who spoke to The New York Times podcast "The Interview" this week, said that things could've been different if an open primary had occurred.
"The anticipation was that, if the president were to step aside, that there would be an open primary," Pelosi said in the interview, which will be released on Saturday.
In regards to Harris entering the race if there were a primary, Pelosi said: "Kamala may have, I think she would have done well in that and been stronger going forward. But we don't know that. That didn't happen. We live with what happened."
She said that things would've went down differently if Biden left the race sooner. She also said that Biden immediately endorsing Harris "really made it almost impossible to have a primary at that time."
The quick endorsement for Harris shut down an idea of a primary when Biden was pushed by many in the Democratic Party, including Pelosi, to exit the race in July after questions of his mental-agility came to light due to his age.
Pelosi also said that cultural issues carried more blame than the working class vote, which Bernie Sanders claimed in a damning post after Harris' election loss.
"It should come to no great surprise that a Democratic Party which has abandoned working class people would find that the working class has abandoned them," Sanders wrote in the statement. "While the Democratic leadership defends the status quo, the American people are angry and want change. And they're right."
Pelosi defended the party from Sanders' claims, and said he "has not won."
"With all due respect, and I have a great deal of respect for him, for what he stands for, but I don't respect him saying that the Democratic Party has abandoned the working-class families," Pelosi said in the interview.