Joseph Joshua Weiss (J J Weiss) (30 August 1905 – 9 April 1972) was a Jewish-Austrian chemist and Professor at the Newcastle University. He was a pioneer in the field of radiation and photochemistry.
Weiss was born in 1905 in Austria. He had obtained a Dipl.Ing. degree in the Technische Hochschule in Vienna. He entered the Textile Institute at Sorau in 1928 and was the head of the chemistry department there. He left his post two years later to become an assistant to the German chemist Fritz Haber at the Kaiser Wilhelm Institute for Physical Chemistry and Elektrochemistry in Berlin. Together they discovered the Haber–Weiss reaction. He fled with Haber (who was born Jewish) from Nazi Germany to Cambridge in 1933. He later moved to University College London, where he got his PhD in 1935 from Prof Frederick George Donnan. in 1937 he started teaching at the King's College in Durham, which later became the Newcastle University.
In 1956 he was appointed a professor of Radiation Chemistry at the Newcastle University.
In 1968 he received an honorary degree from the Technical University of Berlin. In 1970 he received the Marie Curie Medal of the Curie Institute.
In 1972 the Association for Radiation Research established the Weiss Medal, named after him.
In 1942 he married Frances Sonia Lawson.