http://www.marines.mil/news/publications/Documents/MCO P1020.34G W CH 1-5.pdf I've gotten shit for having my hair 1.5 inches long before. General No eccentricities in the manner of wearing head, facial, or body hair will be permitted. If applied, dyes, tints, bleaches and frostings which result in natural colors are authorized. The hair color must complement the person's complexion tone. Color changes that detract from a professional image are prohibited. Fingernails will be kept clean and neatly trimmed so as not to interfere with performance of duty, detract from military image or present a safety hazard. Nail polish for male Marines is not allowed. Nail polish as it applies to female Marines will fall under standards explained below. Males Men will be well groomed at all times and will abide by the following: Hair will be neat and closely trimmed. The hair may be clipped at the edges of the side and back; will be evenly graduated from zero length at the hairline in the lower portion of the head to the upper portion of the head; and will not be over 3 inches in length fully extended on the upper portion of the head; the back and sides of the head below the hairline may be shaved to remove body hair. Sideburns will not extend below the top of the orifice of the ear. Sideburns will not be styled to taper or flare. The length of an individual hair of the sideburn will not exceed 1/8 inch when fully extended. Head hair will be styled so as not to interfere with the proper wear of uniform headgear. Hair which protrudes from beneath properly worn headgear in an unsightly manner is considered excessive, regardless of length. No male Marine will be required to have his hair clipped to the scalp except while he is undergoing recruit training or when such action is prescribed by a medical officer. This does not prohibit a male Marine from having his hair clipped to the scalp if he so desires. Members of the Selected Marine Corps Reserve will comply with these regulations, except that wigs are authorized for periods of inactive duty for training. If worn, wigs will comply with the above grooming regulations. The face will be clean shaven, except that a mustache may be worn. When worn, the mustache will be neatly trimmed and must be contained within imaginary vertical lines from the corners of the mouth and the margin area of the upper lip. The individual length of a mustache hair fully extended must not exceed 1/2 inch. Except for a mustache, eyebrows, and eyelashes; hair may be grown on the face only when a medical officer has determined that shaving is temporarily harmful to the individual's health. In these cases, the medical officer may issue a temporary "shaving waiver." No male Marine will be required to have his chest hair clipped except that which is so long as to protrude in an unsightly manner above the collar of the long sleeve khaki shirt.