A Bachelor of Medicine, Bachelor of Surgery (Latin: Medicinae Baccalaureus, Baccalaureus Chirurgiae; MBBS, also abbreviated as BM BS, MB ChB, MB BCh, or MB BChir) is a medical degree granted by medical schools or universities in countries that adhere to the United Kingdom's higher education tradition. Despite the historical distinction in nomenclature, these degrees are typically combined and conferred together. This degree is usually awarded as an undergraduate degree, but it can also be awarded at graduate-level medical institutions. The typical duration for completion is five to six years In some cases, students with relevant Undergraduate Degrees can join an accelerated program and complete a 4-year MBBS Programme.

A Bachelor of Medicine (BMed, BM, or MB) is an undergraduate medical degree awarded by medical schools in countries following the tradition of China.^{[citation needed]} The completion period for this degree is generally five to six years. The term "Medicine" in this context encompasses the broader field of medical science and practice, rather than specifically internal medicine. Consequently, graduates with a BMed degree are qualified to practice surgery. The BMed degree serves as the primary medical qualification, and individuals holding it may pursue further professional education, such as a Master of Medical Science or a Doctor of Medical Science (equivalent to a PhD).

Both degrees are considered equivalent to the Doctor of Medicine degree typically conferred by universities in North America. In the United States, doctors trained in some osteopathic medicine programs receive the Doctor of Osteopathic Medicine degree. For practical purposes, all these degrees (MBBS/BMed/MD/DO) are considered to be equivalent.

The degree is currently awarded in institutions in the United Kingdom and countries formerly part of the British Empire.

Historically, Bachelor of Medicine was also the primary medical degree conferred by institutions in the United States and Canada, such as the University of Pennsylvania, Harvard University, the University of Toronto, the University of Maryland, and Columbia University. Several early North American medical schools were (for the most part) founded by physicians and surgeons who had trained in England and Scotland. University medical education in England culminated with the Bachelor of Medicine qualification and in Scotland the Doctor of Medicine. In the mid-19th century, the public bodies that regulated medical practice required practitioners in Scotland and England to hold the dual Bachelor of Medicine and Bachelor of Surgery degrees. Over the course of the 19th century, North American medical schools switched to the tradition of the ancient universities of Scotland and began conferring Doctor of Medicine rather than Bachelor of Medicine.

In the countries that award bachelor's degrees in medicine, however, Doctor of Medicine denotes a holder of a junior doctorate and is reserved for medical practitioners who undertake research and submit a thesis in the field of medicine. Nevertheless, those holding Bachelor of Medicine, Bachelor of Surgery are usually referred to by the courtesy title of "Doctor" and use the prefix "Dr.", whether or not they also hold a Ph.D. or DSc.

In many countries, the degrees are awarded after an undergraduate course lasting five or six years. For example, most Chinese universities offering medical degrees provide undergraduate courses lasting six years. In some cases, a graduate in another discipline may subsequently enter a special graduate-entry medical course, reduced in duration to account for relevant material covered or learning skills acquired during the first degree. In some cases the old first-year courses (for six-year degrees) in the basic sciences of physics, chemistry, and biology have been abolished: that standard has to be reached by school examinations before entry. However, in most countries, a newly graduated Bachelor of Medicine and Surgery must spend a specified period in internship before he or she can obtain full registration as a licensed medical practitioner.

The names and abbreviations given to these degrees depend on the institution, awarding body or country, and vary widely. This is mostly for reasons of tradition rather than to indicate any difference between the relative levels of the degrees. They are considered equivalent.