少校是军队的职衔，是校官中的最低级别。英文里，陆军以及由它衍生出来的军种的少校称为Major，海军少校则称为Lieutenant Commander（直译：副指挥官）。英国皇家空军少校则称为Squadron Leader（直译：中队长）。

英国陆军少校主要担任连长职务。美国陆军少校主要担任副营长、营部运行官职务。

******少校精实案前主要担任兵器连连长或不重要的副营长，精实案因为指挥架构修整始改编制担任副营长、营参谋主任、营辅导、营级运行官、本部连、旅部连、群部连、营部连或专业连队连长。

Major is a military rank of commissioned officer, with corresponding ranks existing in many military forces. When used unhyphenated, in conjunction with no other indicators, the rank is just senior to that of an army captain and right below the rank of lieutenant colonel. It is considered the most junior of the field officer ranks.