The Lunar Gateway, or simply Gateway, is a planned space station which is to be assembled in orbit around the Moon. The Gateway is intended to serve as a communication hub, science laboratory, and habitation module for astronauts as part of the Artemis program. It is a multinational collaborative project: participants include NASA, the European Space Agency (ESA), the Japan Aerospace Exploration Agency (JAXA), the Canadian Space Agency (CSA), and the Mohammed Bin Rashid Space Centre (MBRSC). The Gateway is planned to be the first space station beyond low Earth orbit.

The science disciplines to be studied on the Gateway are expected to include planetary science, astrophysics, Earth observation, heliophysics, fundamental space biology, and human health and performance. As of April 2024, construction is underway of the initial habitation and propulsion modules. The International Space Exploration Coordination Group (ISECG), which is composed of 14 space agencies including NASA, has concluded that Gateway systems will be critical in expanding human presence to the Moon, to Mars, and deeper into the Solar System.

The project is expected to play a major role in the Artemis program after 2026. NASA's Budget for FY 2025 included $817.7 million for the project. While the project is led by NASA, the Gateway is meant to be developed, serviced, and used in collaboration with the CSA, ESA, JAXA, and commercial partners. It will serve as the staging point for both robotic and crewed exploration of the lunar south pole and is the proposed staging point for NASA's Deep Space Transport concept for transport to Mars.

The project received complete funding in the 2025 One Big Beautiful Bill Act.

Formerly known as the Deep Space Gateway (DSG), the station was renamed Lunar Orbital Platform-Gateway (LOP-G) in NASA's 2018 proposal for the 2019 United States federal budget. When the NASA budget was signed into law on February 15, 2019, US$450 million had been committed by Congress to preliminary studies.

In November 2019, NASA unveiled the name and logo of the space station inspired by the American frontier symbol of the St. Louis Gateway Arch.

The Apollo Command and Service Module was the first crewed lunar orbiting spacecraft performing dockings and crew transfers with another spacecraft, the Apollo Lunar Module. Lunar bases, like the first Tranquility Base as well as concepts for lunar bases have been the main focus of human presence at the Moon.

An earlier NASA proposal for a cislunar station had been made public in 2012 and was dubbed the Deep Space Habitat. That proposal led to funding in 2015 under the NextSTEP program to study the requirements of deep space habitats. In February 2018, it was announced that the NextSTEP studies and other ISS partner studies would help to guide the capabilities required of the Gateway's habitation modules. The solar electric Power and Propulsion Element (PPE) of the Gateway was originally a part of the now-canceled Asteroid Redirect Mission.