| Type: | Bishop |
| Honorific-Prefix: | His Excellency, The Most Reverend |
| Joseph Maxmillian Mueller | |
| Bishop of Sioux City titular bishop of Simitthu | |
| Church: | Roman Catholic Church |
| See: | Diocese of Sioux City |
| Term: | September 20, 1948 – October 20, 1970 |
| Predecessor: | Edmond Heelan |
| Successor: | Frank Henry Greteman |
| Ordination: | June 14, 1919 |
| Consecration: | October 16, 1947 |
| Consecrated By: | Amleto Giovanni Cicognani |
| Birth Date: | 1 December 1894 |
| Birth Place: | St. Louis, Missouri, US |
| Death Place: | Sioux City, Iowa, US |
| Previous Post: | Coadjutor Bishop of Sioux City 1947 to 1948 |
| Honorific Suffix: | D.D. |
| Education: | Pontifical College Josephinum |
Joseph Maximilian Mueller (December 1, 1894 – August 9, 1981) was an American prelate of the Roman Catholic Church. He served as bishop of the Diocese of Sioux City in Iowa from 1948 to 1970.
Joseph Mueller was born on December 1, 1894, in St. Louis, Missouri, to George Fritz and Barbara (née Ziegler) Mueller.[1] After graduating from SS. Peter and Paul School at St. Louis in 1907, he studied at the Pontifical College Josephinum in Columbus, Ohio.
Mueller was ordained to the priesthood for the Diocese of Belleville on June 14, 1919.[2] He then served as a curate at parishes in Carlyle, Mount Carmel, East St. Louis, and Belleville, all in Illinois. In 1926, Mueller was appointed the founding pastor of Blessed Sacrament Parish in Belleville. From 1930 to 1947, he served as rector of St. Peter's Cathedral Parish in Belleville. He was named a domestic prelate in 1939.
On August 20, 1947, Mueller was appointed coadjutor bishop of the Diocese of Sioux City and titular bishop of Sinda by Pope Pius XII. He received his episcopal consecration on October 16, 1947, from Archbishop Amleto Cicognani, with Bishops Joseph Schlarman and Edward Hunkeler serving as co-consecrators.
On the death of Bishop Edmond Heelan on September 20, 1948, Mueller automatically succeeded him as the third bishop of Sioux City8. As bishop, Mueller built several new schools, churches, and other parish facilities.[3] He also attended all four sessions of the Second Vatican Council in Rome between 1962 and 1965.
On October 20, 1970, Pope Paul VI accepted Mueller's resignation as bishop of the Diocese of Sioux Falls and appointed him as titular bishop of Simitthu. He resigned his titular see on January 13, 1971.
Joseph Mueller died on August 9, 1981, in Sioux City at age 86.