For many current and prospective university students, there's nothing more exciting than browsing the academic catalog for classes. You may not be able to enroll in every class that interests you, depending on the course's qualifying standards. Such is the case with graduate-level classes. Usually, you can't enroll unless you've completed a bachelor's degree, but like most rules, there are exceptions.
Talk to your Adviser
Assuming that your institution has a graduate school, if you're nearing the end of your bachelor's degree program and need to enroll in classes to maintain your full-time student status, ask your academic adviser to approve your request to enroll in graduate-level classes. Your adviser also may approve your request to take such classes if no undergraduate courses of interest to you are offered in a semester. In either case, you have a better chance of being approved if you have a strong GPA.
Ask the Dean
If you're not enrolled in the university and wish to take a graduate-level class, contact the dean of the college. For example, if you wish to take a graduate education class, request permission to enroll from the dean of the education department. You may be required to apply for admissions as a non-degree student and you may be required to submit college-level transcripts to gain approval.