校服（拼音：xiào fú）是学校规定的统一样式的学生服装，中小学学生普遍穿着。校服最早起源于欧洲。学校为了规范管理，统一的着装。
School uniforms (pinyin: xiào fú) are uniform student clothing prescribed by the school and are generally worn by primary and secondary school students. School uniforms first originated in Europe. In order to standardize management, schools have uniform clothing.
一般在学校的重大活动中会要求学生统一着装，一般学校校服有该校校徽，也直接影响到学校形象。在学校的日常生活中，穿上校服能够展现学生精神抖擞、活力飞扬的一面，也是学生青春时代的专属标志。
Generally, students are required to wear uniform clothing during major school events. Generally, school uniforms have the school emblem, which directly affects the school’s image. In daily school life, wearing school uniforms can show students’ energetic and vibrant side, and is also an exclusive symbol of students’ youth.
校服是指学校的制服，在中学和小学十分普遍，也可见于大学、社区学院和幼稚园或其他层级的学校里，一般而言会按照性别、季节、年级等分为许多款式。不同国家和不同的学校的校服款式可能有很大的差别，一些学校甚至可能会对发型做出管理，而对发型的要求即所谓的“发禁”。特定性别制服一直争议的焦点，有的学校允许女学生可选择裤子或裙子。多数地方要求学生上运动堂时穿着运动服，运动服因地而异。校服上通常有校徽，使得校服影响到学校的形象。
引进校服可能对学生的学业表现和行为有正面影响，尽管有些研究认为制服无助改善学生的课业和行为表现，但也有相当数量的研究显示，引进学校制服有助改善学生整体的课业和行为表现。比起没有制服的学校，有制服的学校的老师所感受的校园帮派活动较少，反之比起有制服的学校，没有制服的学校的学生有较高的自我知觉。
即使是没有制服的学校，也往往会对学生的服装做出一定的规范，许多没有明定学校制服的学校的服装指引列明规定，包含透视装、露脐上衣、鼓吹吸烟或酗酒的衣服以及印有对其他同学甚至家长的恶意批评之服装属于违禁，任何学生均不能穿着。而校服指引则是对学生在不同场合该穿着什么服装的规定。
A school uniform is a uniform worn by students primarily for a school or otherwise an educational institution. They are common in primary and secondary schools in various countries and are generally widespread in Africa, Asia, Oceania, and much of the Americas, but are not common in the United States, Canada, and most countries in continental Europe.
An example of a uniform would be requiring button-down shirts, trousers for boys, and blouses and pleated skirts for girls, with both wearing blazers. A uniform can even be as simple as requiring collared shirts, or restricting colour choices and limiting items students are allowed to wear.