A naval division is a sub-division of a squadron or flotilla of a navy. It can also be a sub-division of a fleet. A division is the smallest naval formation, most commonly numbering between two and four ships.
A division is usually commanded by senior flag officer, most commonly a vice admiral or rear admiral, irrespective of the division's size. For example, in the Imperial Japanese Navy, the First Carrier Division was commanded by a rear or vice admiral, same as the 18th Cruiser Division.
Divisions are most commonly grouped by ship class and type, dependent on how the respective nation's navy is organised. Examples of division types include:
| Submarine Division | 24th Submarine Division (Soviet Navy and Russian Navy) | six submarines |
| Minesweeper Division | Mine Division 71 (United States Navy) | two minesweepers |
| Sloop Division | 2nd Escort Group (Royal Navy) | six sloops |
| Destroyer Division | Destroyer Division 22 (United States Navy) | four destroyers |
| Cruiser Division | 18th Cruiser Division (Imperial Japanese Navy) | two light cruisers |
| Battleship Division | Battleship Division 2 (United States Navy) | four battleships |
| Carrier Division | Second Carrier Division (Imperial Japanese Navy) | two aircraft carriers |