施马尔卡尔登联盟（德语：Schmalkaldischer Bund，拉丁语：Foedus Smalcaldicum或Liga Smalcaldica）是在16世纪中期由神圣罗马帝国中信仰路德宗的诸侯所组成的军事防御联盟。该联盟最初于宗教改革开始后创建，其目的是出于宗教动机，但此后其成员逐渐希望它能够取代神圣罗马帝国。这一联盟虽然并非同类首创，但与之前的联盟（如托尔高联盟）不同，施马尔卡尔登联盟有足够的军事实力来保卫其政治和宗教利益。联盟的名称来自于图林根的城镇施马尔卡尔登。

The Schmalkaldic League (German:Schmalkaldischer Bund; Latin:Foedus Smalcaldicum or Liga Smalcaldica) was a defensive alliance of Lutheran princes within the Holy Roman Empire during the mid-16th century. Although originally started for religious motives soon after the start of the Protestant Reformation, its members eventually intended for the League to replace the Holy Roman Empire as their source of political allegiance. While it was not the first alliance of its kind, unlike previous formations, such as the League of Torgau, the Schmalkaldic League had a substantial military to defend its political and religious interests. It received its name from the town of Schmalkalden, which is located in the present-day German state of Thuringia.