The play begins shortly after the death of the Roman emperor, with his two sons, Saturninus and Bassianus, squabbling over who will succeed him. Their conflict seems set to boil over into violence until a tribune, Marcus Andronicus, announces that the people's choice for the new emperor is his brother, Titus, who will shortly return to Rome from a victorious ten-year campaign against the Goths. Titus subsequently arrives to much fanfare, bearing with him as prisoners the Queen of the Goths (Tamora), her three sons, and Aaron the Moor (her secret lover). Despite the desperate pleas of Tamora, Titus sacrifices her eldest son, Alarbus, in order to avenge the deaths of his own sons during the war. Distraught, Tamora and her two surviving sons, Demetrius and Chiron, vow revenge on Titus and his family.
Meanwhile, Titus refuses the offer of the throne, arguing that he is not fit to rule, and instead supporting Saturninus' claim, who is duly elected. Saturninus tells Titus that for his first act as emperor, he will marry Titus's daughter Lavinia. Titus agrees, although Lavinia is already betrothed to Saturninus' brother, Bassianus, who refuses to give her up. Titus's sons tell Titus that Bassianus is in the right under Roman law, but Titus refuses to listen, accusing them all of treason. A scuffle breaks out, during which Titus kills his own son, Mutius. Saturninus then denounces the Andronicus family for their effrontery and shocks Titus by marrying Tamora. However, putting into motion her plan for revenge, Tamora advises Saturninus to pardon Bassianus and the Andronicus family, which he reluctantly does.
During a royal hunt the following day, Aaron persuades Demetrius and Chiron to kill Bassianus, so they may rape Lavinia. They do so, throwing Bassianus' body into a pit, and dragging Lavinia deep into the forest before violently raping her. To keep her from revealing what has happened, they cut out her tongue and cut off her hands. Meanwhile, Aaron frames Titus's sons Martius and Quintus for the murder of Bassianus with a forged letter. Horrified at the death of his brother, Saturninus arrests Martius and Quintus and sentences them to death.
Some time later, Marcus discovers the mutilated Lavinia and takes her to her father, who is still shocked at the accusations levelled at his sons, and upon seeing Lavinia, is overcome with grief. Aaron then visits Titus, falsely telling him that Saturninus will spare Martius and Quintus if either Titus, Marcus or, Titus's remaining son, Lucius, cuts off one of their hands and sends it to him. Titus has Aaron cut off his (Titus's) left hand and sends it to the emperor but, in return, a messenger brings Titus Martius and Quintus' severed heads, along with Titus's own severed hand. Desperate for revenge, Titus orders Lucius to flee Rome and raise an army among their former enemy, the Goths.
Later, Lavinia 'writes' the names of her attackers in the dirt, using a stick held with her mouth and between her mutilated arms. Meanwhile, Tamora secretly gives birth to a mixed-race child, fathered by Aaron. Aaron kills the midwife and nurse and flees with the baby to save it from Saturninus' inevitable wrath. Thereafter, Lucius, marching on Rome with an army, captures Aaron and threatens to hang the infant. To save the baby, Aaron reveals the entire revenge plot to Lucius.
Back in Rome, Titus's behaviour suggests he may have gone insane. Convinced of his madness, Tamora, Chiron and Demetrius approach him, dressed as the spirits of Revenge, Murder, and Rape. Tamora (as Revenge) tells Titus that she will grant him revenge on all of his enemies if he can convince Lucius to postpone the imminent attack on Rome. Titus agrees and sends Marcus to invite Lucius to a reconciliatory feast. Revenge then offers to invite the Emperor and Tamora as well, and is about to leave when Titus insists that Rape and Murder (Chiron and Demetrius) stay with him. When Tamora is gone, Titus cuts their throats and drains their blood into a basin held by Lavinia. Titus morbidly tells Lavinia that he plans to "play the cook" and grind the bones of Demetrius and Chiron into powder and bake their heads.
The next day, during the feast at his house, Titus asks Saturninus if a father should kill his daughter when she has been raped. When Saturninus answers that he should, Titus kills Lavinia, telling Saturninus of the rape. When the Emperor calls for Chiron and Demetrius, Titus reveals that they have been baked in the pie Tamora has just been eating. Titus then kills Tamora, and is immediately killed by Saturninus, who is subsequently killed by Lucius to avenge his father's death. Lucius is then proclaimed Emperor. He orders that Saturninus be given a state burial, that Tamora's body be thrown to the wild beasts outside the city, and that Aaron be buried chest-deep and left to die of thirst and starvation. Aaron, however, is unrepentant to the end, regretting only that he had not done more evil in his life.