Kate Marie Ziegler (born June 27, 1988) is an American competition swimmer who specializes in freestyle and long-distance events.

Ziegler has won a total of fifteen medals in major international competition, including eight golds, five silvers, and two bronzes spanning the World Aquatics and the Pan Pacific Championships.

[citation needed] At the 2004 Short Course Worlds, she finished second to Japan's Sachiko Yamada in the 800-meter freestyle with a time of 8:20.55.

The latter time made her the third-fastest woman (and second-fastest American) in the history of the event, following only world-record holder Janet Evans's 15:52.10 and German Hannah Stockbauer's 16:00.18.

In 2007, at an in-season meet, Ziegler broke Janet Evans's longstanding world record in the 1500-meter freestyle with a time of 15:42.54.

[6] At the 2012 Summer Olympics in London, Ziegler swam in the fastest qualifying heat of 800-meter freestyle and posted a time of 8:37.38, behind Rebecca Adlington of the United Kingdom and Lauren Boyle of New Zealand.