Southend High School for Boys, also known by its initialism SHSB, is a selective secondary Grammar school situated along Prittlewell Chase in Prittlewell, in the north-west of Southend-on-Sea, England, south-west of the roundabout of the A127 and A1159. It teaches students from the age of 11 through to 18 years old, and admission to the school is dependent upon their performance in selective 11+ tests set by the Consortium of Selective Schools in Essex (CSSE). It converted to Academy status on 1 February 2011, and has autonomous control over itself. Student numbers have been increasing over recent years. As of academic year 2008–2009, there are just over 1,150 students on roll, with over 230 of them in the Sixth Form, 20 to 30 of which come from other schools, including girls.
The school consistently achieves over 95% of its students attaining 5 GCSEs grade A*–C each year, and was one of the few schools in the country to achieve "outstanding" in the latest Ofsted inspection.The current Headteacher is Dr Robin Bevan, who has a doctorate in education and was appointed in September 2007, and the previous headmaster was Michael D Frampton, a History teacher who served as Headmaster from 1988 to 2007. The current deputy heads are Mrs E Smith and Mrs R Worth and the assistant head is Mrs C Bates.
Former pupils, teachers, and other members of the school are known as Old Southendians, and are entitled to join the Old Southendian Association (OSA) of past members and alumni, to keep in touch and network with other former pupils at social, sporting, and musical events, and on trips and meals. The OSA has the motto "sustaining friendships", and is one of the oldest and largest Boys Associations in the country, with 2,470 members as of October 2011. The school also has a Parents' Association (PA), which is a registered charity, and associated PA Committee.