A Bachelor of Science (BS, BSc, SB, or ScB; from the Latin baccalaureus scientiae or scientiae baccalaureus) is a bachelor's degree awarded for programs that generally last three to five years.

The first university to admit a student to the degree of Bachelor of Science was the University of London in 1860.

Whether Bachelor of Science or Bachelor of Arts degrees are awarded in particular subjects varies between universities. For example, an economics student may graduate as a Bachelor of Arts in one university but as a Bachelor of Science in another, and occasionally, both options are offered. Some universities follow the Oxford and Cambridge tradition that even graduates in mathematics and the sciences become Bachelors of Arts, while other institutions offer only the Bachelor of Science degree, even in non-science fields.