King's Lynn was a constituency in Norfolk which was represented continuously in the House of Commons of England from 1298 to 1707, in the House of Commons of Great Britain from 1707 to 1800, and in the House of Commons of the United Kingdom from 1801 until it was abolished for the February 1974 general election.

The Parliamentary Borough of King's Lynn, which was known as Lynn or Bishop's Lynn prior to 1537, returned two Members of Parliament until 1885, when its representation was reduced to one member by the Redistribution of Seats Act 1885. It was abolished as a Borough under the Representation of the People Act 1918 and was reconstituted as a Division of the Parliamentary County of Norfolk (from 1950, a County Constituency), absorbing the bulk of the abolished North Western Division. It was abolished for the February 1974 general election, being replaced by the re-established constituency of North West Norfolk.

Sir Robert Walpole, the first Prime Minister, was an MP for the constituency for almost the entirety of his parliamentary career, from 1702 to 1742.

1885–1918

• The existing parliamentary borough, and so much of the municipal borough of King's Lynn as was not already included in the parliamentary borough.^[1]

1918–1950

• The Borough of King's Lynn;
• The Urban Districts of New Hunstanton and Walsoken;
• The Rural Districts of Docking, Freebridge Lynn, King's Lynn, and Marshland (except the parishes of Outwell and Upwell); and
• The Rural District of Downham parishes of Wiggenhall St Germans, Wiggenhall St Mary the Virgin, Wiggenhall St Mary Magdalen, and Wiggenhall St Peter.^[2]

1950–1974

• The Municipal Borough of King's Lynn;
• The Urban District of New Hunstanton; and
• The Rural Districts of Docking, Freebridge Lynn, and Marshland.^[3]

Minor changes to the boundary with South West Norfolk to align with boundaries of local authorities, which had been rationalised.  Also marginal changes to county boundaries with Isle of Ely and Parts of Holland.