The Galactic Patrol was an intergalactic organization in the Lensman science fiction series written by E. E. Smith. It was also the title of the third book in the series.

In the Lensman novels, the Galactic Patrol was a combination military force and interstellar law-enforcement agency, charged with the defense and preservation of Civilization. The Lensmen were the elite of the Galactic Patrol, and Lensmen tended to hold the majority of the senior-executive positions in the Patrol, although non-Lensmen personnel were essential to the organization's success, and garnered almost as much respect as their Lens-bearing superiors. The organization had large numbers of non-humans serving in all roles, although many of the leadership positions seem to be occupied by humanity.

The Patrol had a great deal of political influence in Civilization. In First Lensman, First Lensman Virgil Samms' first Galactic Council was made up entirely of Lensmen, and there was no evidence that the situation had changed in later novels. The Patrol's influence was also present in many other levels of society, to the point where "G-P hours" or "G-P days" were generally considered the standard unit of time, and that they had what amounted to a censorship veto over many prominent news-reporting organizations. Patrol bases dotted the galaxy, ranging from low-grade spaceports to the massive headquarters bases of Prime Base on Earth (or Tellus, as it is called in the novels) and Ultra Prime on Klovia, in the second galaxy, and its possession of the inertialess (or "free") drive made it possible for its forces to deploy anywhere in known space rapidly.

Other forms of faster-than-light travel included Hyper-Tubes, which were man-made wormholes which both the Boskonians and Galactic Patrol frequently used, and N-Space corridors which were gateways to a parallel universe. Both sides of the war frequently used literal planets accelerated to relativistic speeds and "fired" through wormholes as a primary strategic weapon, in effect intergalactic ICBMs. Later the Boskonian Empire began using N-Space corridors as "cannons" that could fire planets or moons at fifteen times the speed of light at a given target and could obliterate suns at intergalactic distances.

This organization was also very well-funded, to the point where even though the tax rate was the lowest in history with a total income tax, in the highest bracket, of only 3.592%, it possessed an expendable reserve of ten billion credits on Tellus alone. In Gray Lensman, Port Admiral Haynes noted that, were it not for the galactic war, a financial crisis might have risen over the Patrol possessing so much in the way of legal tender. (For comparison, in 1940, the year after Gray Lensman was originally published, the U. S. Gross Domestic Product was $97 billion, so the "ten thousand million credit" figure was perceived by readers as equivalent to 10% of GDP; in 2008 terms that would be almost $1.5 trillion.)

Also, the Patrol was well equipped for its second role as military force. In Galactic Patrol it fielded a Grand Fleet of over fifty thousand capital ships, including large numbers of "maulers", or super-heavy battleships. That fleet grew by leaps and bounds through the later novels, numbering well into the millions by Second Stage Lensmen and Children of the Lens. The number of combat units in the Grand Fleet were so numerous that a special flagship, the Directrix or Z9M9Z, had to be commissioned with extensive and advanced C3.

It is explicitly stated in later novels that the Directrix/Z9M9Z is in command of "one-million combat units", which is further elaborated upon as literally one-million individual fleets. The exact number of ships in each fleet is unknown, but the defensive fleet for Directrix alone was eighty ships, and this could reasonably be said to be the number of other fleets—or approximately 80,000,000 ships in total. This also leads to a fair estimation of the size of Civilization, since each fleet was based on an individual member-world of Civilization, indicating about one-million planets in total. This number does not include a fleet of uninhabited planets converted into mobile, armored weapons (also explicitly mentioned) and a huge, planet sized, antimatter WMD called a "Negasphere".

This number is in keeping with the fact that, later in the series, Boskone (the great enemy of Civilization) mustered fleets of warships and mobile worlds of comparable size to be sent through the "hundreds of thousands" of hyperspatial tubes they'd opened to attack Arisia and Earth directly. It is possible then that at that one battle Boskone possessed millions or even tens of millions of ships equal in size and power to super-maulers, thus explaining Civilization's need for such astonishingly vast standing armed forces.