| Masaki Iwai | |
| Birth Date: | 31 July 1985 |
| Birth Place: | Hyogo Prefecture, Japan[1] |
| Skip: | Yusuke Morozumi |
| Third: | Yuta Matsumura |
| Second: | Ryotaro Shukuya |
| Lead: | Masaki Iwai |
| Alternate: | Kosuke Morozumi |
| World Championship Appearances: | 1 |
| Pacific Championship Appearances: | 1 |
is a Japanese curler from Takarazuka, Hyōgo.
After winning the 2018 Japanese curling championship,[2] Iwai skipped the Japan national team at the 2018 World Men's Curling Championship. Iwai threw third stones on the team which also consisted of fourth Go Aoki, second Ruyotaro Shukuya and lead Yutaka Aoyama. Iwai led the team to a 3-9 round robin record, an 11th-place finish.
Iwai began the 2018-19 curling season by winning the Hokkaido Bank Curling Classic,[3] his first World Curling Tour event win.