Katherine, Katharine, or Catherine Smith may refer to:

• Catharina Smith or Catherine Smith (fl. c. 1807), English novelist and actress
• Cat Smith (born 1985), British Labour Party politician
• Catherine Smith, Baroness Smith of Cluny (born 1973), British lawyer and government minister
• Karen Zerby (born 1946), real name Katherine Smith
• Katharine Smith Salisbury (1813–1900), sister to Latter Day Saints founder Joseph Smith
• Katherine Smith (Navajo activist) (1918–2017), Navajo activist, cultural educator, and resistor
• Katherine Smith (footballer) (born 1998), Australian rules footballer
• Katherine Douglas Smith (1878 – after 1947), British suffragette
• Catherine Smith (died 1944), wife of Al Smith and First Lady of New York
• Katharine Smyth (fl. 2019), American memoirist

• Cath Smith, character in Gavin & Stacey
• Kathy Smith (disambiguation)
• Kathryn Smith (disambiguation)
• Kate Smith (disambiguation)