The town has three secondary schools with sixth forms: Carre's Grammar School, a boys' grammar school, Kesteven and Sleaford High School, a selective academy girls' grammar school, and St George's Academy, formerly St George's College of Technology, and before that Sleaford (County) Secondary Modern School (mixed non-selective secondary school).
The grammar schools are selective and pupils are required to pass the Eleven plus exam.
St George's is not selective.
The co-educational Joint Sixth Form consortium allows pupils to choose subjects taught at all three schools.

Carre's Grammar School was founded in 1604 by a bequest of Robert Carre of Aswarby.
It has received Specialist Sports and Science statuses, became an academy in 2011 and was judged to be "good" by Ofsted in 2013, at which time it had 817 pupils, including the co-educational sixth form.
Sleaford and Kesteven High School for Girls was established in 1902.
It has specialist art status, became an academy in 2011 and was judged to be "good" by Ofsted in 2013, at which time there were 825 pupils on roll, including those in the co-educational sixth form.
St George's opened in 1908 as Sleaford Council School.
It has received specialist technology college status, converted to an academy in 2010 and operates a satellite school at Ruskington.
St George's had 2,247 pupils on roll in 2012, across both sites and including the sixth form; when assessed by Ofsted in that year, was judged to be "good".
The town has three secondary schools with sixth forms: Carre's Grammar School, a boys' grammar school, Kesteven and Sleaford High School, a selective academy girls' grammar school, and St George's Academy, formerly St George's College of Technology, and before that Sleaford (County) Secondary Modern School (mixed non-selective secondary school). The grammar schools are selective and pupils are required to pass the Eleven plus exam. St George's is not selective. The co-educational Joint Sixth Form consortium allows pupils to choose subjects taught at all three schools.
Carre's Grammar School was founded in 1604 by a bequest of Robert Carre of Aswarby. It has received Specialist Sports and Science statuses, became an academy in 2011 and was judged to be "good" by Ofsted in 2013, at which time it had 817 pupils, including the co-educational sixth form. Sleaford and Kesteven High School for Girls was established in 1902. It has specialist art status, became an academy in 2011 and was judged to be "good" by Ofsted in 2013, at which time there were 825 pupils on roll, including those in the co-educational sixth form. St George's opened in 1908 as Sleaford Council School. It has received specialist technology college status, converted to an academy in 2010 and operates a satellite school at Ruskington. St George's had 2,247 pupils on roll in 2012, across both sites and including the sixth form; when assessed by Ofsted in that year, was judged to be "good".
Sleaford