Iwona Marcinkiewicz (born 23 May 1975) is an athlete from Poland. She competes in archery.

Marcinkiewicz represented Poland at the 2004 Summer Olympics. She placed 28th in the women's individual ranking round with a 72-arrow score of 628. In the first round of elimination, she faced 37th-ranked Yukari Kawasaki of Japan. Marcinkiewicz defeated Kawasaki, winning 119-106 in the 18-arrow match to advance to the round of 32. In that round, she faced Zhang Juanjuan of China, losing to the 5th-ranked archer 166-157 in the regulation 18 arrows. Marcinkiewicz finished 20th in women's individual archery.

Marcinkiewicz was also a member of the 15th-place Polish women's archery team.