Count Carl Gustaf Dücker (1663 – 3 July 1732) was a Swedish field marshal (Fältmarskalk) and Royal Councillor. Born in Livonia, Dücker began his career fighting for the French in the Nine Years' war. At the start of the Great Northern War, Dücker became a subordinate to King Charles XII and served under him with distinction during the Polish and Russian campaigns. Dücker was taken prisoner following the disastrous battle of Poltava, but was released soon after in a prisoner exchange. Upon returning to service, he fought against Coalition forces in Swedish Pomerania, most notably during the siege of Stralsund. After being taken prisoner once again, he returned to Sweden in early 1718 and participated in the siege of Fredriksten.