The charity said it plans to pursue a judicial review in the Edinburgh Court of Session over the granting of consent to four projects off the east coast last October.
It claims the government did not properly consider the impact on birds that would result from the construction of the 784MW Inch Cape, 450MW Neart na Gaoithe, 525MW Seagreen Alpha, and 525MW Seagreen Bravo projects.
"These decisions raise important questions about how the laws that are designed to protect our country's most important places for wildlife, and the birds that depend on them, are applied," the RSPB said.
The Scottish government said it is aware of the RSPB's intentions, but has not yet received official notification of any legal action.
"We are confident that the decisions taken are correct and robust and will vigorously defend any action," it said.
While the RSPB has challenged a number of consents for offshore wind projects, it remains supportive of the developments in principal.
A study welcomed by the charity in December found the vast majority of seabirds alter their flight paths in order to avoid collisions with offshore wind turbines.