The NMUN Dress Code adheres to professional business attire guidelines. Typically, delegates wear business suits to the Opening and Closing Ceremony and to all committee sessions. All clothing must adhere to guidelines that portray professionalism and modesty. International delegates in whose native countries traditional cultural dress is appropriate may dress in "professional business dress". These delegates are the only individuals to whom this applies. Any delegate attempting to use cultural costume to portray a "character" will be asked to leave the committee chamber and change into clothing that is more appropriate. If a delegate's attire is deemed inappropriate by the NMUN staff the delegate will be asked to leave the session and return with the appropriate attire. Also, note that it is inappropriate for delegates to display any national symbols such as flags, pins, crests, etc. on their person during committee sessions. UN symbols, however, are acceptable.

The Dress Code Guidelines are as follows:

Women: Standard female delegate attire for the conference is business jacket, skirt or slacks, button blouse, and dress shoes. Shirts that expose excessive bare skin on the chest, stomach or are otherwise revealing are inappropriate. Clothes that reveal undergarments are inappropriate.

Men: Standard male delegate attire for the conference is business jacket, slacks, button down shirt with tie and dress shoes. Shirts that expose excessive bare skin on the chest, stomach or are otherwise revealing are inappropriate. Clothes that reveal undergarments are inappropriate. Facial hair should be shaved or trimmed neatly. Dress sweaters are generally considered too casual, as well as shorts, ball caps, jeans, sneakers and sunglasses.