The minnesinger Tannhäuser, having spent a year in the realm of Venus, the goddess of love, longs to return to the human world – he longs for a simpler, earthly life, and springtime filled with the sounds of church bells. He sings a song praising Venus who has showered him with love and ends by asking her to let him go. Surprised, Venus promises him even greater pleasures but her attempts to change his heart are unsuccessful. Tannhäuser insists and repeats his pleas, and Venus furiously curses his desire for salvation. Tannhäuser cries out that his hope rests with the Virgin Mary. In an instant, Venus’s spell is broken and she disappears. Tannhäuser suddenly finds himself in a valley near the Wartburg castle on a warm, sunny spring day in May.
The ringing of herder’s bells is heard; a young shepherd is singing his song. A procession of pilgrims passes on the way to Rome, and the shepherd stops playing. Tannhäuser is deeply moved and praises the wonders of God, as horns announce the arrival of a hunting party. It is Landgrave Hermann with his knights. Recognizing Tannhäuser as their long-lost friend, they beg him to return to the castle with them, but Tannhäuser is reluctant. Wolfram, one of the knights, reminds him that his singing once won him the love of Elisabeth, the Landgrave’s niece. On hearing her name, he happily follows them into the castle.
Elisabeth joyfully greets the Wartburg’s Hall of Song, which she has not set foot in since Tannhäuser left. She has secluded herself since Tannhäuser's departure several years prior. Tannhäuser is led in by Wolfram. Elisabeth, at first shy and confused, tells Tannhäuser how she has suffered in his absence, but then joins him in praise of love. The two share a happy moment. Wolfram too loves Elisabeth but, observing their emotional reunion, Wolfram realizes that his own affection is hopeless.
Landgrave Hermann is delighted to find his niece in the Hall of Song, and together they welcome their guests who have come for a song contest. The Landgrave declares love the subject of the competition and promises the victor to receive whatever he asks from the hand of Elisabeth. Wolfram opens the contest with a heartfelt tribute to idealized love. Tannhäuser, his thoughts still on Venus, replies with a hymn to worldly pleasures, to the horror of the guests. As the men draw their swords, Elisabeth throws herself between the parties to protect Tannhäuser and begs the knights for mercy. The Landgrave pronounces his judgment: Tannhäuser will be forgiven if he joins the pilgrims on their way to Rome to do penance and to seek the Pope's forgiveness.
Months go by and, broken-hearted, Elisabeth seeks news of Tannhäuser from each passing pilgrim. A group of pilgrims, back from Rome, passes by, but Tannhäuser is not among them. Broken with grief, Elisabeth prays to the Virgin Mary to receive her soul into heaven. Wolfram has devoted himself to Elisabeth even though she has never returned to him a love as deep as his. He asks the evening star to guide her way.
Night falls, and a solitary pilgrim approaches. It is Tannhäuser, ragged and weary. He tells Wolfram of his devout penitence on the way to Rome – of his joy at seeing so many others pardoned, and of his despair when the Pope proclaimed that he could no more be forgiven for his sins than the papal staff bear green leaves. Left without hope, all he wants now is to return to Venus. He summons her and she appears, just as Wolfram once again brings Tannhäuser to his senses by invoking Elisabeth’s name. At this moment, Elisabeth’s funeral procession comes winding down the valley. Venus disappears. Tannhäuser implores Elisabeth to pray for him in heaven and collapses dead. As dawn breaks, another group of pilgrims arrives, telling of a miracle: the Pope’s staff, which they bear with them, has blossomed.