Twomey (Irish: Ó Tuama) is an Irish Gaelic clan based most prominently in what is today County Cork. The paternal ancestors of the clan are of the Corcu Loígde; the Twomey clan originated from Donnchadh na Tuaima who was himself a member of the O'Leary family.^{[citation needed]} The Twomey family motto is "fortis undis et armis" which translates to 'strong waves and arms'.^{[citation needed]}

Twomey Ó Tuama
Parent house	Corcu Loígde
Country	Munster & Desmond
Founder	Donnchadh na Tuaima

Notable people with the surname include:

• Anne Carolyn Twomey (born 1951), American stage, film, and television actress
• Anne Frances Twomey, Australian legal academic
• Bill Twomey Jr. (1927–1996), Australian rules football player
• Bill Twomey Sr. (1899–1977), Australian rules football player
• Billy Twomey (born 1977), Irish equestrian
• Chris Twomey (born 1954), American artist and filmmaker
• Christina Twomey, Australian historian
• Cillian Twomey, Irish geriatric consultant
• Clare Twomey (born 1968), British visual artist and researcher
• David Twomey (born 1961), Australian rules footballer
• Frank Twomey (born 1950s), Irish actor and impressionist, known for the children's television programme Bosco
• Hugh Twomey (1920–1989), Canadian physician and politician
• Jeremiah F. Twomey (1874–1963), New York politician
• Jeremiah Twomey (1847–1921), journalist and Member of the New Zealand Legislative Council
• Joanne Twomey, American politician from Maine
• Joe Twomey (fl. mid-20th century), Irish hurler
• John Twomey (disambiguation), several people
• Kay Twomey (1914–1995), American songwriter and music arranger
• Liam Twomey (born 1967), Irish Fine Gael politician from Wexford
• Margaret Twomey (born 1963), Australian diplomat; ambassador to Russia (2008–2012)
• Mathilda Twomey, Seychellois lawyer and academic
• Mick Twomey (1931–2015), Australian rules football player
• Moss (Maurice) Twomey (1897–1978), Irish republican; chief of staff of the IRA
• Nora Twomey (born 1971), Irish animator and filmmaker
• Pat Twomey (1929–1969), Australian rules football player
• Patrick Twomey (1892–1963), New Zealand community worker; secretary of the Leper Trust Board
• Paul Twomey (born 1961), American business consultant; CEO of ICANN
• Seamus Twomey (1919–1989), Irish republican; twice chief of the Provisional IRA
• Seán Ó Tuama (1926–2006), Irish poet, playwright and academic
• Seán Twomey (born 2000), Irish hurler
• Sharon Twomey (born 1964), Irish actress
• Vincent Twomey (born 1941), Irish priest
• Vincy Twomey (1929–1993), Irish hurler
• Wayde Twomey (born 1986), Australian rules footballer