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

From his early childhood, Adamczyk wanted to become an actor. He attended the Machulski 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 by attending the Theatre Academy in Warsaw. During his second academic year, he won a scholarship from the Soros Foundation, which allowed him to attend the British American Drama Academy for one year, where he performed Hamlet for his diploma.