Erik Wilhelm "Loppan" Adlerz (23 July 1892 – 8 September 1975) was a Swedish diver who competed at the 1908, 1912, 1920 and 1924 Summer Olympics.

Four years later he won gold medals in the 10 m platform and plain high diving.

In 1920 he won the silver medal in the 10 m platform; in the plain high diving event he finished fourth next to three Swedish teammates.

In 1924 he finished fourth in the 10 m platform and failed to reach the final in the plain high diving.

[2] He was the elder brother of Märta Adlerz, who competed in swimming at the 1912 Olympics.