The Honourable William Frederick Barton Massey-Mainwaring was an Irish art collector and Conservative Party politician in the United Kingdom.
- Occupation
- politician, barrister
- Position held
- member of the 27th Parliament of the United Kingdom, member of the 26th Parliament of the United Kingdom
- Citizenship
- United Kingdom of Great Britain and Ireland
- Born
- May 28, 1845, 1845
- Died