In the military of various countries, ensign is a junior rank of commissioned officer.

Until 1871 the lowest grade of commissioned officers in infantry regiments of the British army had the title of ensign (now replaced by that of Second Lieutenant). It is the duty of the officers of this rank to carry the colours of the regiment. In the 16th century "ensign" was corrupted into "ancient," and was used in the two senses of a banner and the bearer of the banner.

In the United States Navy, the rank of "Ensign" superseded in 1862 that of "Passed Midshipman". It designates an officer in the United States Navy or the United States Coast Guard ranking with a Second Lieutenant in the army. A typical Ensign is at specialty training for up to two years after receipt of the commission, depending on specialty, and after that is a division officer, leading a group of petty officers and enlisted personnel in a Division . U.S. Navy and Coast Guard Ensigns wear a collar insignia of a single gold bar, hence their nickname of "butterbars" (shared with Army, Air Force and Marine 2nd Lieutenants).

The most senior U.S. Navy ensign on board ship or in a naval aviation squadron receives an enlarged collar insignia, often engraved with the word "BULL", and is known as the "Bull Ensign". By tradition, this officer is responsible for guiding and mentoring the other ensigns of a ship or squadron's wardroom. The Bull Ensign is also the direct social superior to the J.O.R.G. Ensign, or "George" (Junior Officer Requiring Guidance) who is the most junior officer in a naval command. The "George" normally serves as the Vice-President of the mess at formal military dinners, or "mess nights", and has key responsibilties for the success of this important military social event.

Ensigns are listed as pay grade O-1 in the United States Armed Forces.

Royal New Zealand Navy

The Royal New Zealand Navy, unlike the Royal Navy—whose uniforms, insignia, and traditions it copies—created the Ensign grade to equal the lowest commissioned RNZAF grade of Pilot Officer and the New Zealand Army grade of Second Lieutenant. It ranks above the grade of Midshipman. Like the grade of Pilot Officer, it uses a single thin strip of braid. The fact that the Royal Navy has no real equivalent to the lowest commissioned Royal Air Force and British Army grades was the driving factor behind the RNZN's decision to create the Ensign grade, as well as the fact that at the time New Zealand was actively involved with the United States Armed Forces, it also made sense to balance the rank system out with that used by the United States Navy.

See also

• U.S. Navy officer rank insignia
• Comparative military ranks