Catherine Michelle "Katie" Meili (born April 16, 1991) is a former American competitive swimmer, who won a bronze medal at the 2016 Summer Olympics in the 100 meter breaststroke and a gold medal for swimming the preliminary heats of the 4 × 100-meter medley relay.
Meili was born in Carrollton, Texas, and her hometown is Colleyville, Texas. She graduated from Nolan Catholic High School in 2009 and Columbia University in 2013. She planned to attend Georgetown Law School in fall 2017.
In 2014, Meili won the 100-yard freestyle and 200-yard individual medley events at the short-course winter national championships in Greensboro, North Carolina. At the 2015 US Nationals in San Antonio, Texas, she won her first long-course national title, in the 100-meter breaststroke. At the 2015 Pan American Games in Toronto, Canada, she won the gold medal in the 100-meter breaststroke. In the heats she broke the Pan Am Games record with a time of 1:05.64. At the Duel in the Pool meet in December 2015, she broke the world record in the 4×100-meter medley relay (short course) together with her teammates Courtney Bartholomew, Kelsi Worrell, and Simone Manuel.