Members: Hans Poulsen, John Pugh (2), Ted Baarda

18th Century Quartet (alternatively 18CQ or Eighteenth Century Quartet) was an Australian band from Melbourne, Victoria formed in 1964.

Original lineup, 1964-65:
Hans Poulsen (vocals, guitars, bouzouki, mandolin, balalaika, banjo, bongos)
Ted Baarda (vocals, guitars, harmonica, clarinet, tambourine)
Ron Snellgrove (vocals, violin, guitar)
Dave Graham (acoustic bass) early 1964
Steve Dunstan (acoustic bass, piano, sarod, kalimba) late 1964-1965
Barry Duggan (flute, sax) - recording only

Second lineup, 1966-67:
Hans Poulsen (vocals, guitars, bouzouki, mandolin, balalaika, banjo, bongos) early 1966
Keith Glass (guitar, vocals)
John Pugh (violin, autoharp, guitar)
Frank Lyons (bass)
Dennis "Fred" Forster (drums)
Bob Lloyd (drums)
Randall Wilson (drums)
Julius Colman (violin) early 1967