Gilbert Jackson (c.1595/1600 - after 1648) was an English portrait painter active ca. 1621–1640s.
Never associated with the court, Jackson primarily painted portraits of provincial gentry and members of the professions. His work period is bracketed by the signed 1621 portrait of Edward Somerset, 4th Earl of Worcester and the 1643 signed and dated portrait of Chief Justice Sir John Bankes (1643), at Kingston Lacy in Dorset.
Little is known of Jackson's personal life. He likely trained in London under one of the masters of the Jacobean era, and after a career spanning twenty years, was made free of the Painter-Stainers' Company on 16 December 1640. His place in English portraiture is summed up in this assessment by Lane Fine Art:
His Art is purely English, and little influenced by the arrival in England of such painters as Paul van Somer, Daniel Mytens or Anthony Van Dyck. His work looks back to the flat hieratic style of the late Elizabethan Court, and he devotes infinite care to the rendition of surfaces, colours and textures whilst seeming to be indifferent to the niceties of perspective. The result is a mixture of sophisticated painterly technique allied with a naiveté of drawing which is at once deeply old-fashioned in the new world of the Baroque, and infinitely charming and unselfconscious.