Portrait of Adele Bloch-Bauer I (also called The Lady in Gold or The Woman in Gold) is an oil painting on canvas, with gold leaf, by Gustav Klimt, completed between 1903 and 1907. The portrait was commissioned by the sitter's husband, Ferdinand Bloch-Bauer, a Viennese and Jewish banker and sugar producer. The painting was stolen by the Nazis in 1941 and displayed at the Österreichische Galerie Belvedere. The portrait is the final and most fully representative work of Klimt's golden phase. It was the first of two depictions of Adele by Klimt—the second was completed in 1912; these were two of several works by the artist that the family owned.

Adele died in 1925; her will asked that the artworks by Klimt be eventually left to the Galerie Belvedere, although these works belonged to Ferdinand, not her. Following the Anschluss of Austria by Nazi Germany, and due to the Nazi persecution of Jews, Ferdinand fled Vienna, and made his way to Switzerland, leaving behind much of his wealth, including his large art collection. The painting was stolen by the Nazis in 1941, along with the remainder of Ferdinand's assets, after a false charge of tax evasion was made against him. The lawyer acting on behalf of the German state gave the portrait to the Galerie Belvedere, claiming he was following the wishes Adele had made in her will. Ferdinand died in 1945; his will stated that his estate should go to his nephew and two nieces.

In 1998 the Austrian investigative journalist Hubertus Czernin established that the Galerie Belvedere contained several works stolen from Jewish owners in the war and that the gallery had refused to return the art to their original owners or to acknowledge a theft had taken place. One of Ferdinand's nieces, Maria Altmann, hired the lawyer E. Randol Schoenberg to make a claim against the gallery for the return of five works by Klimt. In 2006 after a seven-year legal claim, which included a hearing in front of the Supreme Court of the United States, an arbitration committee in Vienna agreed that the painting, and others, had been stolen from the family and that it should be returned to Altmann. She sold it the same year for $135 million, at the time a record price for a painting to the businessman and art collector Ronald Lauder to place the work in the Neue Galerie, the public New York–based gallery he co-founded.