Mecklenburg-Strelitz was a duchy in northern Germany, consisting of the present day district of Mecklenburg-Strelitz and the area around Ratzeburg. It was established in 1701, roughly on the territory of the former duchy of Mecklenburg-Güstrow. The Capital was Neustrelitz. In 1933 it was united with the neighbouring state of Mecklenburg-Schwerin to the state of Mecklenburg (today part of the Bundesland Mecklenburg-Western Pomerania).

The US county Mecklenburg (Charlotte, North Carolina) is named after Mecklenburg-Strelitz and Strelitz-born princess Charlotte (queen of King George III of the United Kingdom). The flower Strelitzia ("Bird of Paradise") also is in honor of her home country. Queen Luise of Prussia also was a born princess of Mecklenburg-Strelitz.