Pelosi, the first female House speaker, defeated moderate Democratic Rep. Heath Shuler of North Carolina despite massive party losses in congressional elections. Democrats had lost at least 60 House seats on Nov. 2.
Many House Democrats defended Pelosi, who said the bad economy and high unemployment were the reasons for her party's election losses.
Boehner faced no opposition and will become speaker in the new Congress.
The Associated Press contributed to this report.