John B[ryan?] Weller (February 22, 1812–August 17, 1875) was Governor of California from January 8, 1858 to January 9, 1860 and a Congressman from Ohio, U.S. Senator from California and Ambassador.

Born in Hamilton County, Ohio, he attended the public schools and Miami University in Oxford, Ohio. He then studied law, was admitted to the bar and practiced in Butler County, Ohio. He was prosecuting attorney of Butler County from 1833 until 1836.

He 1838 he was elected as a Democrat from Ohio to the 26th, 27th and 28th Congresses, serving from 1839 until 1845.

He served in the Mexican-American War from 1846 until 1847, and then was an unsuccessful Democratic candidate for Governor of Ohio in 1848.

In 1849 and 1850 he was a member of the commission to establish the boundary line between California and Mexico. He then moved to California and engaged in the practice of law. He was elected as a Democrat from California to the United States Senate for the term commencing March 4, 1851, and served from January 30, 1852, to March 3, 1857, but was an unsuccessful candidate for reelection. During the 34th Congress he was chairman of the U.S. Senate Committee on Military Affairs . He was then elected Governor of California and served 1858 to 1860.

After leaving the state house, he was appointed Minister to Mexico in 1860 and was recalled in 1861. He moved to New Orleans, Louisiana in 1867 and continued the practice of law.

He died in New Orleans in 1875. Original interment at Laurel Hill Cemetery in San Francisco, his remains were moved to Girod Street Cemetery , that burying ground was destroyed in 1959 and unclaimed remains were commingled with 15,000 others and deposited beneath Hope Mausoleum, St. John's Cemetery, New Orleans.