第一次里昂公会议（Lyons I）是天主教会第十三次的大公会议，于1245年在法国里昂召开。

第一次里昂公会议由教宗依诺增爵四世主持。依诺增爵四世被扬言攻打罗马的神圣罗马帝国皇帝腓特烈二世威胁，在1244年12月2日抵达里昂，并于隔年年初召集教会主教开会。大约250名主教回应了这次召集，包括拉丁礼君士坦丁堡宗、拉丁礼安提阿宗主教与阿奎莱亚（威尼斯）及140名主教。拉丁皇帝鲍德温二世、图卢兹伯爵的雷蒙德七世与普罗旺斯伯爵的雷蒙·贝朗热四世都有参加。当时罗马处于皇帝腓特烈二世的围困下，教宗召开会议以逐出及废位皇帝，以及葡萄牙国王桑乔二世。会议同时指示了新的一次十字军东征（见第七次十字军东征），这次是由法国国王路易九世所带领，以收回圣地为目标。

The First Council of Lyon (Lyons I) was the thirteenth ecumenical council, as numbered by the Catholic Church, taking place in 1245.

The First General Council of Lyon was presided over by Pope Innocent IV. Innocent IV, threatened by Holy Roman Emperor Frederick II, arrived at Lyon December 2, 1244, and early the following year he summoned the Church's bishops to the council later that same year. Some two hundred and fifty prelates responded including the Latin Patriarchs of Constantinople, Antioch, and Aquileia (Venice) and 140 bishops. The Latin emperor Baldwin II of Constantinople, Raymond VII, Count of Toulouse, and Raymond Bérenger IV, Count of Provence were among those who participated. With Rome under siege by Emperor Frederick II, the pope used the council to excommunicate and depose the emperor with Ad Apostolicae Dignitatis Apicem, as well as the Portuguese King Sancho II. The council also directed a new crusade (the Seventh Crusade), under the command of Louis IX of France, to reconquer the Holy Land.