Szymon Marciniak (born 7 July 1981) is a Polish association football international referee. Marciniak became a FIFA referee in 2011. He refereed at 2014 FIFA World Cup qualifiers, beginning with the Group F match between Portugal and Azerbaijan. On 30 June 2015 he was the head referee at the 2015 UEFA European Under-21 Championship Final. In April 2016, he was criticized for not giving a penalty against Bayern Munich in the first leg of the UEFA Champions League quarter-finals.