As per the Student Information Handbook:

The school dress code described below will be in effect at NPS between the hours of 0730 and 1700, Monday through Friday (less holidays) or at any other time when meeting with and greeting visiting personnel in an official capacity. The academic quad, the library and the Presidio of Monterey Army Health Clinic and NMAU constitute locations where this dress code is in effect.

Business Casual is the standard attire for students. You are expected to dress and conduct yourself in a manner appropriate to a business environment at all times while on campus. Business casual does not have a requirement for a coat or tie. Specifically, it includes a dress quality collared shirt or turtleneck and dress slacks for men and either a dress or dress blouse, dress slacks/skirt for women. Shirt and shoes should be of similar style and quality. Socks are required. Pressed khakis and turtlenecks are acceptable but do not include collarless shirts and flight deck jerseys. Logos on the collar or extreme logos elsewhere on the garment are not permitted. The uniform equivalent to "Business Casual" consists of Service Khaki for Navy and the open-collared equivalent uniform for other services.  Designated attire established herein represents a minimum expectation.  Nothing in this policy precludes dressing to a higher standard.