This is a comprehensive list of Headmasters of the Royal Grammar School, Guildford since 1554. There have been 35 headmasters since the granting of the Royal Charter, which established the post of headmaster:^[1]

• 1554 - 1555 ? Lawson
• 1555 - 1556 Thomas Baker
• 1556 - 1569 Thomas Jervard
• 1569 - 1575 Roger Goad
• 1575 - 1580 Francis Taylor
• 1580 - c.1584 John Stanford
• c.1584 - 1589 Thomas Parvish
• 1589 - 1594 John Good
• 1594 - 1603 John Crow
• 1603 - 1623 James Bladworth
• 1623 - 1633 William Hill
• 1633 - 1645 George Holmes
• 1645 - 1698 John Graille
• 1698 - 1718 Samuel Pigot
• 1718 - 1722 John Randal
• 1722 - 1733 George Stevens
• 1733 - 1756 Cornelius Jeale
• 1756 - 1769 John Pearsall

• 1769 - 1804 Samuel Cole
• 1804 - 1819 William Hodgson Cole
• 1819 - 1822 John Stedman
• 1822 - 1837 Henry Ayling
• 1837 - 1852 Joseph Belin
• 1852 - 1859 Frederick James Fairhead
• 1859 - 1874 Henry Gordon Merriman
• 1874 - 1879 Charles Henry Jeaffreson
• 1879 Edward J. Piggott (temporary appointment)
• 1879 - 1889 Sidney Bolton Kincaid
• 1889 - 1919 John Charles Honeybourne
• 1919 - 1942 Arthur John Bradford Green
• 1942 - 1967 Michael Duncan Hallowes
• 1967 - 1975 Wilfred Harry Hore
• 1975 - 1992 John Daniel
• 1992 - 2007 Timothy Mark Stuart Young
• 2007–present Jonathan Mark Cox