The Geneva Convention (II) for the Amelioration of the Condition of Wounded, Sick and Shipwrecked Members of Armed Forces at Sea (French: Convention pour l'amélioration du sort des blessés, des malades et des naufragés des forces armées sur mer), more commonly referred to as the Second Geneva Convention or Geneva Convention II and abbreviated as GCII, is one of the four treaties of the 1949 Geneva Conventions. It was first adopted in 1949, replacing the Hague Convention (X) of 1907. It adapts the main protective regime of the First Geneva Convention to combat at sea.

Geneva Convention II is a lengthy document consisting of 63 articles. The most essential provisions of the treaty are:

For a detailed discussion of each article of the treaty, see the original text and the commentary. There are currently 196 countries party to the 1949 Geneva Conventions, including this second treaty but also including the other three.