Joseph Mullens (September 2, 1820 - July 10, 1879) was an English missionary. Born in London, Mullens studied at Coward College (a dissenting academy that trained nonconformist ministers, i.e. ministers that did not conform with the Church of England) and graduated in 1837. He continued his education at the University of London (which was affiliated with Coward College) and graduated in 1841. Then, he continued his education in Edinburgh with the intention of working in India with the London Missionary Society (LMS). Mullens was ordained in September 1843 and soon after was on his way to India, where he joined the mission of Swiss missionary Alphonse François Lacroix near Calcutta. He married Lacroix's daughter, Hannah Catherine (who was fluent in Bengali), on June 19, 1845. Mullens continued to rise through the missionary ranks and returned to England on leave in 1858. A gifted publicist, throughout his career Mullens advocated for Protestant missionaries in general, not only those of the LMS. He returned to India in 1860, not long after a conference of Protestant missionaries in Liverpool. His wife Hannah died in India not long after their return, on November 21, 1861. Mullens was named joint foreign secretary for the LMS in 1865, and soon took a tour of LMS missions in China and India. He became the only foreign secretary in 1868. He toured the United States and Canada promoting the LMS in 1870. Mullens toured LMS missions in Madagascar in 1873. In 1879, while accompanying two inexperienced missionaries on a trip to Lake Tanganyika who were to replace the deceased incumbent there, Mullens fell ill and died. He was buried at a mission at Mpwapwa.