The Sophienburg Museum and Archives is a public museum located in New Braunfels, Texas, United States. It was established in 1933 as a museum and library by residents of New Braunfels. The library section of the building would eventually be converted into the city's archive. It occupies the site of the former headquarters of the Adelsverein, the Prussian colonization effort of Texas. The museum contains an extensive collection of artifacts which reflect the history and rich German-Texan heritage of the area. It is a Texas Historic Site.

Prince Carl of Solms-Braunfels, a German prince put in charge of the Adelsverein, ordered the construction of "Sophienburg" (transl. Sophie's castle) in 1845, named after his wife Princess Sophie. At that point, Sophienburg was a log fortress constructed on a hilltop in what became New Braunfels. The fortress served as the headquarters of the Adelsverein until the campaign's bankruptcy in 1847. Sophienburg was left abandoned until 1926, when New Braunfels' residents purchased the site of the original fortress; in 1933, they established a museum chartered by the state of Texas and a library. After the construction of multiple other public libraries in the city, the library was converted into the city's archive.

The museum memorializes New Braunfels' origin as a German colony, its strong German roots, and the city's history and progression as a whole. It comprises over 100,000 artifacts spread across a rotating collection of exhibits. Among the exhibits are displays demonstrating the belongings of the original German settlers of the New Braunfels area. Artifacts from later residents of the area, including clothing, furniture, and tools, are also on display. The archives store over one million photographs, documents, and maps, some of which originate from the original German settlement of the area. The museum also contains a gift shop, which sells genuine German items.

Throughout 2019, the museum hosted an exhibit memorializing the impact of World War I on the majority-German town. It commemorated its 90th anniversary in 2023 with an outdoor celebration and the opening of three additional exhibits. The museum also hosts an occasional "Bürger Ball", a dance and social event similar to those held by the town's residents in the early 20th century. In 2022, the Texas Travels Awards named the Sophienburg Museum as its best big-market museum in Texas.