who killed joffrey in game of thrones

Joffrey Baratheon was killed by poison during his wedding feast, an event known as the "Purple Wedding" in Game of Thrones. The murder was orchestrated by Lady Olenna Tyrell with the assistance of Petyr Baelish (Littlefinger). Littlefinger smuggled the poison into King's Landing hidden in a hairnet given to Sansa Stark, and Olenna used it to poison Joffrey's wine. Their motive was to protect Margaery Tyrell, Olenna's granddaughter, from marrying the cruel and sadistic Joffrey. Although Tyrion Lannister was initially blamed and arrested for the murder, it was later revealed by Olenna herself before her death that she was the mastermind behind the assassination, wanting to spare Margaery from Joffrey's brutality and to weaken the Lannisters' hold on power