Charles I (28 December 1540 in Neustadt – 22 July 1610 in Güstrow), was the reigning Duke of Mecklenburg in the Mecklenburg-Güstrow part of the country.

He was the youngest son of the Duke Albert VII and his wife, Anna of Brandenburg.

Between 1564 and 1610, Charles was administrator of the commandry of the Order of Saint John at Mirow.

On 17 August 1603, during an outbreak of plague in the region, he had an audience with the English diplomat Stephen Lesieur at Neukloster near Wismar.

[1] When in 1603 Ulrich died, Charles I tasked John VII's widow, Sophia of Schleswig-Holstein-Gottorp with the guardianship and regency of Mecklenburg-Schwerin on behalf of her minor sons Adolf Frederick I and John Albert II.