Kate O'Brien may refer to:

• Kate O'Brien (novelist) (1897–1974), Irish novelist and playwright
• Kate O'Brien (cyclist) (born 1988), Canadian track cyclist and bobsledder
• Kate Cruise O'Brien (1948–1998), Irish writer
• Kate O'Brien (The Drew Carey Show), a character from The Drew Carey Show

See also

• Catherine O'Brien (disambiguation)
• Cathy O'Brien (disambiguation)
• Kate O'Brian, founder of O'Media Strategies
• Katie O'Brien (born 1986), British professional tennis player
• Katy O'Brien (Fair City character), from the Irish television series Fair City