Yasuji Miyazaki (宮崎 康二, Miyazaki Yasuji) (October 15, 1916 – December 30, 1989) was a Japanese swimmer who competed at the 1932 Summer Olympics in Los Angeles.

Miyazaki was born in Kosai, Shizuoka Prefecture, Japan.

In the semi-finals of the 100 m freestyle event, he surpassed the Olympic record previously set by American champion Johnny Weissmuller with a time of 58.2 seconds, and won the gold medal.

The following day, as part of the team competing in the 4 × 200 m freestyle relay event, he won a second gold medal, with the team setting a new world record of 8 minutes 58.4 seconds.

After his return to Japan, he entered Keio University and retired from competitive sports.