Rusokastro Rock (Bulgarian: скала Русокастро, ‘Skala Rusokastro’ ska-'la ru-so-'kas-tro) is a twin rock at the north entrance to McFarlane Strait in the South Shetland Islands, Antarctica extending 170 m in northwest-southeast direction and 70 m wide, with its two parts separated by a 30 m wide passage. It is situated 1.6 km (0.99 mi) northeast of Pyramid Island, 5.7 km (3.54 mi) northeast of Williams Point on Livingston Island, and 5.7 km (3.54 mi) northwest of Duff Point on Greenwich Island.