<p>It depends what you mean by “allowed”. Southpasdena has painted too bleak a picture. Not too many classes in letters and sciences are restricted to majors-only, and most don’t have required prerequisites. So from that point of view, even as an engineer you can sign up for most other classes and the registrar will allow you to enroll.</p>
<p>However engineering requires a certain number of units you must take for your distribution requirements (General Ed, or GE), and furthermore they have a list of what classes you are allowed to take for those units. Junior and senior year the program allows for one free elective or GE each quarter, although realistically most of them will need to be GE’s to finish in 4 years. There is room for taking some free electives not on the list, but not all that many. So it all depends on what you have in mind. </p>
<p>Take a look at the links on <a href=“http://www.ece.ucsb.edu/undergrad.shtml#degree[/url]”>http://www.ece.ucsb.edu/undergrad.shtml#degree</a> to see how many free electives you have to choose from and what classes are approved for the distribution requirements. The docs are “College of Engineering General Education Requirements”, and "2007-2008 “College of Engineering Announcement” for sample curriculums.</p>