During the mid-1700s, when Louisiana was part of the Spanish Empire, Catholic settlers from Spain, France, and Germany started arriving in the Lafayette area.

Starting in 1755, they were joined by numerous French Acadians whom the British had expelled from their homes in present-day Nova Scotia.

Pope Benedict XV erected the Roman Catholic Diocese of Lafayette in Louisiana on January 11, 1918, with territory taken from the Archdiocese of New Orleans.

[2] In March 1923, a crowd in Lafayette was on the verge of starting a race riot after being incited by the Ku Klux Klan.

[12] In 1948, Jeanmard established the Immaculata Minor Seminary in Lafayette, a high school/college program for teenage boys entering the priesthood.

[13] In 1952, Jeanmard became the first bishop in the Deep South to ordain an African-American man to diocesan priesthood when he conferred holy orders upon Louis Ledoux.

In November 1955, Jeanmard excommunicated two women from Erath, Louisiana, after they assaulted a woman who taught an integrated catechism class.

During his tenure, Schexnayder built a new chancery building, expanded the Immaculata Minor Seminary, established 31 parishes and ordained 81 priests.

[21] John Paul II appointed Reverend Harry Flynn from the Diocese of Albany as coadjutor bishop in 1989 to assist Frey.

In 2002, John Paul II appointed Charles Jarrell of the Roman Catholic Diocese of Houma–Thibodaux as bishop of Lafayette in Louisiana.

[36] In 2014, Minnesota Public Radio obtained documents from a 1988 lawsuit filed by the diocese against its insurers over sexual abuse claims.

[38] In October 2018, Reverend David Broussard received a five-year prison sentence after pleading guilty to possession of child pornography.

Louisiana State Police had found 500 images of child pornography on his computer during a search of the rectory at St. Bernard Parish in Breaux Bridge.

[43] In April 2019, the diocese released a list of 33 diocesan clergy who were credibly accused of committing acts of sex abuse.

[44][45] The Louisiana Supreme Court said in June 2024 that it would allow a "look back" period in which victims of sexual abuse could sue their perpetrators, despite the statute of limitations.