Duke Paulus Atreides is a fictional character in Frank Herbert's Dune universe. He is the father of Duke Leto Atreides, and husband of Lady Helena Atreides .

Paulus was the reigning Duke of House Atreides and ruler of Caladan. He always said that you should never marry for love, but for gain. His own wife, Lady Helena of House Richesse never loved him, and while he was fond of her early in their marriage, the fondness had largely faded by the time their son reached his majority. Their marriage was arranged so that both House Atreides and House Richesse could gain from it. House Atreides was granted Landsraad status thanks to this union.

Lady Helena plotted against her husband, she knew that by killing him her son, Leto, would ascend and she believed she could use Leto to rule the Dukedom as she saw fit. Helena arranged that a stable worker, who was also from the home planet of House Richesse, was to poison a Salusan Bull with a stimulant that would make it stronger and more savage.

When the Old Duke, who was a skillful bullfighter, fought the Bull he found that it did not seem to tire at all. Then when he started to suspect that something was amiss, Paulus stabbed the Bull with his prod and injected it with the lethal substance that was supposed to kill it. However, the substance, instead of killing the bull, made it angrier and it rampaged and soon killed the Duke.

Thufir Hawat, loyal mentat to the Duke, shot the bull dead but was too late to save the Old Duke.

Leto suspected his mother was behind this, and when it had been proven he had her banished to live with the Sisters of Isolation . He would rather have had her executed but thought it in the best interest that the people should never know of her treachery. The followers of House Atreides were the most loyal anywhere; they loved their leaders. Knowledge of the treachery of Helena would cause much havoc.