Nils Hesslén (2 September 1728 – 13 April 1811) was a Swedish bishop, university professor, and a founder of the Royal Physiographic Society in Lund.

[1] Hesslén was born in Visseltofta, Scania, Sweden, to Måns Sunesson, a farmer and district judge (häradsdomare) and Sara Månsdotter.

After the death of Bishop Petrus Munck in July 1803, he received the majority of the votes in the election and was appointed – because of the absence of King Gustav IV Adolf due to the war – to the episcopate only in March 1805.

He was installed by Archbishop Jacob Axelsson Lindblom in the summer of 1805 and served as bishop of the Diocese of Lund until his death, without making any particular impact there.

He became renowned for his good financial standing and amassed a considerable fortune; he was also known for his satirical attacks on those who opposed him.