The 210 mm gun M1939 (Br-17) (Russian: 210-мм пушка образца 1939 года (Бр-17)) was a Czechoslovak heavy siege gun used by the Soviet Union during World War II.

As a result of the Molotov–Ribbentrop Pact the Germans sold both designs to the Soviet Union.

It is not entirely clear that Škoda actually built the weapons itself or merely supplied the blueprints.

The Br-17 could be broken down into three loads for transport and it used the same carriage, firing platform and control mechanism as the 305 mm howitzer M1939 (Br-18).

By 1941, three Br-17's were in Soviet service, and this number increased to nine by 22 June 1941, when production ceased.