Johan August Arfwedson (12 January 1792 – 28 October 1841) was a Swedish chemist who discovered the chemical element lithium in 1817 by isolating it as a salt.

The younger Arfwedson matriculated as a student at the University of Uppsala in 1803 (at the time, matriculating at a young age was common for aristocratic and wealthy students), completed a degree in Law in 1809 and a second degree in mineralogy in 1812.

In Stockholm, Arfwedson knew the chemist Jöns Jakob Berzelius and received access to his private laboratory, where he discovered the element lithium in 1817, during analysis of the mineral petalite.

In 1818 and 1819, Arfwedson made a European journey, partly in the society of Berzelius.

He spent the larger part of his remaining life administering and multiplying his inherited wealth.