Martha Longenecker (May 18, 1920 – October 29, 2013) was an American artist, Professor of art, and founder of the Mingei International Museum in San Diego, California.

[6] Longenecker undertook postgraduate research in Japan, where she studied from Shoji Hamada (1894–1978) and Tatsuzo Shimaoka (1919–2007).

[5][4] In 2007, Longenecker received an Honorary Doctorate of Fine Arts degree from San Diego State University.

Longenecker oversaw the development of the first Mingei museum, which opened in May 1978 at University Town Centre in San Diego.

[5][2] Longenecker also oversaw the architectural design and the development of the Mingei International Museum at a new facility located at Plaza Dr Panama in Balboa Park in San Diego, which opened in August 1996.

[5][2][3] Following a stroke, on October 29, 2013, Longenecker died at Scripps Memorial Hospital in La Jolla, San Diego, California.