KING EDWARD VI GRAMMAR SCHOOL was founded in November 1550 by order of King Edward VI with the local landowners, the Willoughby d'Eresby family endowing the School to the sum of £13. 13s. 8d. per annum. The School to be funded and administered by Foundation Governors. There was to be a school building, a master's house and 3 and 1/2 acres of land from the Royal Estates in Spilsby. It seems the Parsonage became home to both the house and schoolroom. The School was to be for boys only although girls would be educated in a separate building, which is thought was established in the mistress's house. Matters progressed very slowly until Lord Willoughby d'Eresby gave a house and schoolroom in 1611 , but there appears to have always been a lack of funds - very poor salaries for the master and overall funding too low. During this century the school went downhill and by 1716 a public appeal for funds had to be made. At this time it was decided to set up a new school with 126 people subscribing. A new school building was planned in 1732 - a building 40ft. X 18ft. facing onto Church Street and this three storey building ( reduced to its present 2 storeys in 1864) formed the basis of the school buildings as they exist today. In 1786 a plot of land to the west of the school was leased for 60years for the building of a 'substantial 2 storey house' to the west of the schoolroom - this house is the present 14 Church Street. In 1818, when the Rev Isaac Russell was appointed master the School the School was doing well and Rev Russell was allowed to build a house abutting the schoolroom( between it and No. 14 Church Street) and this together with the school gave accommodation for 100 boys. However as the century progressed the School again began to go downhill and in the early 1900's the Local Education Authority wanted to withdraw its support and the School was in danger of closing. However the Governors, led by Colonel Swann, again appealed for public support, Colonel Swann purchased land to the east of the Schoolroom and in an ambitious scheme the Governors borrowed some £2300, building the 'Swann1 extension of 'four classrooms and the usual offices' helped by a donation from the Exors of the late Mrs. Stainton The biggest change however was that the new buildings allowed girls to be admitted for the first time and the school continued to be 'co-ed' until its closure - there generally being more girls than boys on roll. In the 1930's further plots of land were purchased in Pools Lane enabling the new block to be built and opened in 1938. This contained a Hall with stage, art room, domestic science room, dining room and kitchen etc. and greatly increased the scope of the school and bringing it more in line with similar establishments. From its inception the School had always had difficulty balancing its budget and the 1970s and 80s brought more of these problems - pupil numbers, subject teaching despite liaising with the Franklin School and staffing levels proving ever more difficult and the School finally closed at the end of the summer term 1990.

September 1990 saw the opening of the Spilsby High School incorporating the King Edward VI Grammar School and the Franklin Secondary Modern School and occupying the former Franklin School site, although the County Council continued to use the Grammar School site until upgrading of the Franklin site was completed in 1998. The new School has successively been renamed 'King Edward VI School', 'King Edward VI Humanities College' and in 2011 become the 'King Edward VI Academy.'

All the former Grammar School buildings have been sold - those fronting Church Street, being grade II listed have remained, although in private ownership. The remainder of the building have been demolished and the site is now a residential estate.

Funds from the sale of the properties had been invested and the Foundation Trustees now give financial support to the new Academy, local Primary Schools and by giving grants to former pupils going on to further education.