Head girl and head boy

Head boy and head girl are roles of prominent representative student responsibility. The terms are commonly used in the British education system and in private schools throughout the Commonwealth.
United Kingdom and Ireland.
In some British schools, the pupil body elects a head boy and/or a head girl from the pupils/students. Head boys and head girls are usually responsible for representing the school at events, and therefore must be able to make public speeches. They also serve as a good role model for students, and share pupils' ideas with the school's leadership. They may also be expected to lead fellow prefects in their duties. Deputy head boys and girls may also be appointed, taking on the day-to-day management of the prefects in some institutions, as well as looking after the school and creating a link between teachers and pupils. Some schools in the UK have abolished the titles of head boy and head girl entirely, and replaced them with a single role of "head pupil".
The process of selection of a head boy and/or a head girl varies according to school. At most, the student body of the school will have to vote for the heads. The votes would then inform the Heads of School's decisions. This is often preceded with an interview (and more currently an action plan for the academic year).
Other Commonwealth countries.
Some schools in Antigua and Barbuda, Australia, Bangladesh, Barbados, Belize, Botswana, Brunei, Cameroon, Canada, Dominica, Fiji, Gambia, Ghana, Grenada, Kenya, Kiribati, Lesotho, Malawi, Malaysia, Malta, Mauritius, Mozambique, Namibia, Nauru, New Zealand, Nigeria, Pakistan, Papua New Guinea, Republic of Cyprus, Rwanda, Samoa, Seychelles, Sierra Leone, Singapore, Solomon Islands, South Africa, Sri Lanka, St Christopher and Nevis, St Lucia, St Vincent and the Grenadines, Swaziland, The Bahamas, Tonga, Trinidad and Tobago, Tuvalu, Uganda, United Republic of Tanzania, Vanuatu, Zambia and Zimbabwe follow the same system as that in the United Kingdom, having a head girl and head boy or head prefect, a vice-head girl/boy, prefects, house captains, monitors and class representatives. The head girl and boy assist the teachers and administration of the school. Nigerian and Ghanaian schools follow a similar system although some schools appoint a head prefect or senior prefect and assistant senior prefect. Another term used is "Senior Ring" (for boys) and "Senior Pin" (for girls), which is used in some schools such as Aden Bowman Collegiate in Saskatoon, Saskatchewan.
In Australia, the system is much the same as that of the United Kingdom. Almost all public secondary schools will have a student council with each year group having elected representatives. The head boy and head girl are generally the "chair" of this council and will represent the school on a government or community level and will represent the students at the school level.
Equivalent terms.
Class president is a similar position; these are commonly found in high school and secondary schools in the United States and Canada and may or may not necessarily be gender-specific.