The Bachelor of Science in Nursing (BSN, BScN) also known in some countries as a Bachelor of Nursing (BN) or Bachelor of Science (BS) with a Major in Nursing is an academic degree in the science and principles of nursing, granted by an accredited tertiary education provider. The course of study is typically three or four years. The difference in degree designation may relate to the amount of basic science courses required as part of the degree, with BScN and BSN degree curriculums requiring completion of more courses on math and natural sciences that are more typical of BSc degrees (e.g. calculus, physics, chemistry, biology) and BN curriculums more focused on nursing theory, nursing process, and teaching versions of general science topics that are adapted to be more specific and relevant to nursing practice. Nursing school students are generally required to take courses in social and behavioral sciences and liberal arts, including nutrition, anatomy, chemistry, mathematics, and English. In addition to those courses, experience in physical and social sciences, communication, leadership, and critical thinking is required for a bachelor's degree. BSN programs typically last 2–4 years. Someone who holds a BSN can work in private or public medical and surgical hospitals, physician's offices, home health care services, and nursing facilities. Having a BSN can result in more opportunities and better salary than just an associate degree.

The bachelor's degree prepares nurses for a wide variety of professional roles and graduate study. Course work includes nursing science, research, leadership, and related areas that inform the practice of nursing. It also provides the student with general education in math, humanities and social sciences. An undergraduate degree affords opportunities for greater career advancement and higher salary options. It is often a prerequisite for teaching, administrative, consulting and research roles.

A Bachelor of Science in Nursing is not currently required for entry into professional nursing in all countries. In the US, there has been an effort for it to become the entry-level degree since 1964, when the American Nurses Association (ANA) advanced the position that the minimum preparation for beginning professional nursing practice should be a baccalaureate degree education in nursing. The Institute of Medicine (IOM) affirmed in 2010 that nurses should achieve higher levels of education and training through an improved education system that promotes seamless academic progression.