Marie Melchior Joseph Théodose de Lagrené, (14 March 1800, in Amiens – 26 January 1862, in Paris), was a French legislator and diplomat, who hailed from an old family from Picardie. He joined the French diplomatic service at a young age and served in the foreign ministry under Mathieu de Montmorency and accompanied him to the Congress of Verona in 1822. The following year, Lagrené became an envoy at the French embassy in Russia and he subsequently fulfilled the same function at the French embassy in Constantinople. In 1828, he obtained the rank of ambassador while serving at the French embassy in Madrid. Lagrené remained in office after the establishment of the July Monarchy in 1830 and held a number of prominent position in the French foreign service.
In 1843, the French king Louis Philippe sent Lagrené to China in order to conclude a commercial treaty securing the same privileges as the Sino-British Treaty of Nanking. On 24 October 1844, Lagrené and Qiying concluded the Treaty of Whampoa, which legalized the practice of Christianity in China and opened the way for missionary activities.
After the fall of the July Monarchy in 1848, Lagrené briefly left the government, but in 1849 he was elected the representative of the Somme to the French legislative assembly, where he consistently supported conservative causes such as the restriction of suffrage. Following Louis-Napoléon's coup d'état in 1851, Lagrené finally retired from public life.