Joseph James Cella (/ˈsɛlə/ SELL-əh; born November 14, 1969) is an American diplomat and political advisor, who served concurrently as the United States Ambassador to Fiji, Kiribati, Nauru, Tonga, and Tuvalu from 2019 to 2021. A prominent Roman Catholic, Cella co-founded the National Catholic Prayer Breakfast and Catholic Vote.