Piotr Aleksander Adamczyk (Polish: Piotr Aleksander Adamczyk, Polish pronunciation: [ˈpjɔtraˈdamt͡ʂɨk]; born 21 March 1972) is a Polish actor of film, television, dubbing and theatre. He is known for his roles as pianist and composer Frédéric Chopin in the biographical film Chopin: Desire for Love (2002), Pope John Paul II in the television miniseries Karol: A Man Who Became Pope (2005) and its sequel Karol: The Pope, The Man (2006), Thomas in the Marvel Cinematic Universe series Hawkeye (2021) on Disney+, and Sergei Nikulov in the Apple TV+ original science fiction space drama series For All Mankind (2021–2024).

From early childhood, Adamczyk dreamed of becoming an actor. He attended Machulski's youth theatre group in Warsaw. Thanks to an international scholarship, he was able to attend international theatre workshops in the United Kingdom and Germany. He continued his acting education at the Theatre Academy in Warsaw. In his second year, he received a Soros Foundation scholarship, which allowed him to study for a year at the British American Drama Academy, where he performed Hamlet for his diploma.

After graduating from the Theatre Academy, Adamczyk was accepted into the Teatr Współczesny in Warsaw. However, his film career developed much more intensively. He played Stavrogin in Fyodor Dostoevsky's Demons. His breakthrough role was that of Frédéric Chopin in Chopin: Desire for Love — and he became a Polish star.

The peak of his popularity came with his performance in the title role of another Polish historical figure in a two-part Italian television film — Karol: A Man Who Became Pope and Karol: The Pope, The Man. The film was seen by several tens of millions of viewers, and it made him popular in Italy, Latin America and many other Catholic countries.