The business school allows a few undergraduates to take some of their courses. The exceptions are made on a case‐by‐case basis by special arrangement with the instructor and the student services office of the business school. You’ll find information about what classes are available and how to go about enrolling in them at the GSB website for non-GSB students.
Be aware that the deadlines and expectations for business school courses are different from those of the undergraduate programs and that no accommodations will be made by the business school. You will see these spelled out at the GSB site, but some examples: