| Anthony I | |
| Count of Oldenburg | |
| Noble Family: | House of Oldenburg |
| Father: | John V, Count of Oldenburg |
| Mother: | Anna of Anhalt-Zerbst |
| Spouse: | Sophie of Saxe-Lauenburg |
| Issue: | Catherine, Countess of Hoya Anna, Countess of Schwarzburg-Sondershausen John VII, Count of Oldenburg Christian of Oldenburg Clara of Oldenburg Anthony II, Count of Oldenburg |
| Birth Date: | 1505 |
| Death Date: | 22 January |
| Death Place: | Oldenburg |
| Religion: | Lutheranism, prev. Roman Catholicism |
Anthony I, Count of Oldenburg and Delmenhorst (150522 January 1573) was a member of the House of Oldenburg and was the Imperial Count of the Counties of Oldenburg and Delmenhorst within the Holy Roman Empire of German Nation. His parents were John V, Count of Oldenburg (1460–1525) and Anna of Anhalt-Zerbst.
Anthony I was the youngest son of John V. He had a long-running dispute with his brothers John VI, George, and Christopher about who would be the sole ruler of the County of Oldenburg. In 1529, he became the regent of the county. In 1531, Emperor Charles V enfeoffed him with the County of Oldenburg-Delmenhorst.
In 1547, during the Schmalkaldic War, he conquered the Castle and Lordship of Delmenhorst, which had been lost to Münster in 1482.
He strengthened the defenses of his county by expanding his fortresses. He paid for these construction projects from the proceeds of church properties he had stolen during the Reformation. The Order of St. John sued him about their stolen possessions; after a lengthy trial, Anthony prevailed.
With the assistance of farmers from Stadland and Butjadingen, which his father had conquered in 1514, he managed to gain a large amount of fertile territory by constructing levees around some wetlands in the Jade Bight. He constructed several large manors to manage this new land.
In 1566, his brother Christopher died, and Anthony became the sole ruler of Oldenburg and Delmenhorst.
Anthony I died in Oldenburg in 1573 and was succeeded by his son John VII.
Anthony married on 1 January 1537 in Oldenburg, to Duchess Sophie of Saxe-Lauenburg (d. 7 October 1571 in Oevelgönne), the daughter of Duke Magnus I and Catherine of Brunswick-Wolfenbüttel. They had the following children: