I have added content related to the United States but these concepts apply wherever around the world relative to the laws in place. Read the concepts and PLEASE understand this is in NO WAY LEGAL CONSULTATION. Moonlighting is a term used to refer to holding a second job outside of normal working hours. According to the U.S. Department of Labor, about 7 to 8 million Americans -- about 5+ percent of all workers -- work multiple jobs moonlighting while working for a private employer is governed by the policies of the employer. Public employees seeking to hold a second job may be subject to federal laws and agency regulations, depending on the position and classification. Outside employment policies vary by employer but typically define a certain amount of time spent devoted to other activities, which may be compensated or uncompensated. Outside employment policies may require disclosure of outside employment or approval of outside employment. Such policies are promulgated out of concerns regarding conflicts of interest, a distraction from job performance quality or scheduled work hours, misuse of employer's resources, the appearance of impropriety, and others. Misrepresentation or confusion of others may be a concern. For example, when an employee runs their own accounting business, there may be a concern that his/her accounting customers think the work is performed by the employee under the auspices of the company. Outside employment is generally defined as 1) employment or consulting in outside work or activity, 2) receipt from an outside source of a regular retainer fee or salary, or 3) regular or periodic involvement with a business or company in which the employee has a principal interest or a non-profit organization in which the faculty is an officer, board member, etc. In federal government employment, employment essentially includes any compensated non-federal employment or business relationship for providing personal services. Compensation may be direct, indirect, or deferred (actual and necessary expenses not included). Different federal agencies have their own policies, so the outside employment policy of the particular agency needs to be consulted to determine applicable requirements. Outside employment regulation also depends on the classification of the employee. For example, special government employees (SGEs) generally don't have to obtain prior approval. An SGE is appointed to perform temporary duties on a full-time or intermittent basis, with or without compensation, for no more than 130 days of any period of 365 consecutive days. Full-time, non-career presidential appointees (generally presidential appointees with Senate confirmation) may not receive any outside earned income for outside employment. E.O. No. 12674. Full-time, non-career SES employees may not: Have outside earned income exceeding 15% of the annual basic salary for level II of the Executive Schedule, or receive compensation for: providing professional services (e.g., legal) or allowing their name to be used by an entity providing such services; serving as an officer or board member of any association, corporation, or other entity; or teaching, without the prior approval Members of a Uniformed Service (Army, Navy, Marines, Air Force, etc.) on active duty may not receive pay from another government position, except during terminal leave, or unless specifically authorized by law. Enlisted personnel may be employed part-time during off-duty hours in the Department of Defense non-appropriated fund activities. Members of the Armed Forces Reserves and members of the National Guard may receive military pay and allowances, in addition, to pay from another Government position. Federal civilian retirees will have their salary reduced by the amount of their annuity unless an exception is approved, and retirees under age 70 may have their social secu