The Bolshaya Koltsevaya line (Russian: Большая кольцевая линия), known in English as the Big Circle Line, designated Line 11 and 11A is an under construction rapid transit line of the Moscow Metro. When complete, it will become the third circle line on the system, running outside of the existing circle Koltsevaya line and interlocking with Moscow Central Circle, with a temporary branch to Delovoy Tsentr station in Moscow International Business Center.

The first section of the line opened on 26 February 2018 with expected completion of the final stage in 2022. When complete, the line will include 31 stations including three from the existing Kakhovskaya line and over 66 kilometers of track. In November 2017 the city estimated the total cost of the project at 501 billion rubles, up from earlier estimates of 378.9 billion rubles.

Formerly known as the Third Interchange Contour, the city adopted «Bolshaya koltsevaya liniya» as the official name of the line after a vote via the «Active Citizen» web portal.

The working name of the project since inception was the Third Interchange Contour; however, prior to the opening of the line, the city authorities consulted residents to help decide on the name. In an initial survey on the Active Citizen survey website in October 2017, only 34% of the city’s residents voted to keep the working name.

Although retaining the working name was the most popular option, members of the city’s council on transportation infrastructure suggested another vote. Two reasons cited by transport expert Kirill Yankov were that all of the line’s names to this point were in the feminine grammatical gender and that all the other line names were generally understood from a point of view of geography. The city held another vote on its website to allow citizens to choose between the existing name or the Bolshaya Koltsevaya line (Large Circle Line). Of the alternate names suggested by voters in the first vote, Bolshaya Koltsevaya was the most popular, with 9,000 votes.

In the second vote, Bolshaya Koltsevaya was selected with 53.3% of the votes versus 36.5% for the Third Interchange Contour.