The Andromeda Galaxy, also known as Messier 31 or M31, is larger than the Milky Way Galaxy. Both galaxies are spiral galaxies and are part of the Local Group, a cluster of galaxies that includes several other smaller galaxies.
The Andromeda Galaxy has a diameter of approximately 220,000 light-years, making it slightly larger than the Milky Way, which has a diameter of about 100,000 light-years. However, it's important to note that size comparisons between galaxies can be complex, as galaxies can have different shapes, masses, and components.
The Andromeda Galaxy and the Milky Way are on a collision course and are expected to merge in the distant future, forming a larger elliptical galaxy known as Milkomeda or the Milkdromeda galaxy.