Johan Gadolin was born in Åbo (Finnish name Turku), Finland (then a part of Sweden).  Johan was the son of Jakob Gadolin, professor of physics and theology at Åbo. Johan began to study mathematics at the Royal Academy of Turku (Åbo Kungliga Akademi) when he was fifteen. Later he changed his major to chemistry, studying with Pehr Adrian Gadd, the first chair of chemistry at Åbo.
In 1779 Gadolin moved to Uppsala University. In 1781, he published his dissertation Dissertatio chemica de analysi ferri ("Chemical dissertation on the analysis of iron"), under the direction of Torbern Bergman. Bergman founded an important research school, and many of his students, including Gadolin,  Johan Gottlieb Gahn, and Carl Wilhelm Scheele, became close friends.