Quinlan and Francis Terry Architects, Liam O'Connor Architects, Benjamin Tindall Architects, Donald Insall Associates and the former boss of the Westminster Abbey restoration Donald Buttress have all made it in to the final five.
The eventual winning scheme - which will be picked by a jury including the Prince of Wales - will be built just off The Mall on a site near George VI's statue.
The brief for the project is largely open, but recommends rejecting the use of water, a move presumably related to the debacle surrounding the Diana Memorial Fountain in Hyde Park.
Donald Buttress, responsible for the completion of the external restoration of Westminster Abbey between 1973 and 1995, plans to subtly redesign the site, and include a bronze relief or bust of the Queen Mother.
Donald Insall Associates, which worked on the Battle of Britain Monument on the Embankment and Park Lane's Animals in War memorial, will collaborate with sculptors Philip Jackson and Paul Day.
Insall plans to revamp the whole of the site using a bronze statue of the Queen Mother and bronze plaques to illustrate key moments in her life.
Liam O'Connor, who worked on the Commonwealth Memorial Gates in central London, will collaborate with artist Vivien Mallock. The duo plan to create 'a lasting and dignified memorial to honour the legacy of one of the defining personalities in Britain in the 20th century'.
Quinlan and Francis Terry Architects will work with sculptors Tim Lees and Harry Brockway. The father and son team are proposing to build a Classical stone memorial, using traditional techniques with carvings reflecting the life and work of the Queen Mother.
Benjamin Tindall Architects has teamed up with sculptor Jill Watson. The pair aim to design a monument which will incorporate a statue of the Queen Mother alongside her husband King George VI and tell the story of her life, as well as showing her interests and 'famous sense of fun'.
The designers will now submit drawings and costed proposals and the winner will be announced in August.