Franz Joseph Weissmann (Knittelfeld, Austria, 1911 – Rio de Janeiro, RJ, 2005) was a sculptor, draftsman, painter, and teacher. 

He moved to Brazil in 1921. In Rio de Janeiro, between 1939 and 1941, he attended courses in architecture, sculpture, painting, and drawing at the National School of Fine Arts (Enba). From 1942 to 1944, he studied drawing, sculpture, modeling, and casting with August Zamoyski (1893-1970). In 1945, he moved to Belo Horizonte, where he taught private lessons in drawing and sculpture. Three years later, Guignard (1896-1962) invited him to teach sculpture at the Escola do Parque, which later became known as the Guignard School. Initially, his work was based on figuration. From the 1950s onward, he gradually developed a constructivist approach, emphasizing geometric forms, subjecting them to cuttings and folds, and using sheets of iron, steel wires, and aluminum in rod or sheet form. He joined the Grupo Frente in 1955. 

The following year, he returned to Rio de Janeiro and participated in the National Concrete Art Exhibition in 1957. He was one of the founders of the Neoconcrete Group in 1959. That year, he traveled to Europe and the Far East, returning to Brazil in 1965. In the 1960s, he exhibited the "Amassados" (Crushed) series, created in Europe with zinc or aluminum sheets worked with hammers, mallets, and cutting tools, temporarily aligning himself with informalism. Later, he returned to focusing on constructive movements. In the 1970s, he received the award for Best Sculptor from the São Paulo Association of Art Critics (APCA), participated in the International Outdoor Sculpture Biennale in Antwerp, Belgium, and the Venice Biennale. 

He created monumental sculptures for public spaces in various Brazilian cities, such as in Praça da Sé, São Paulo; Parque da Catacumba, Rio de Janeiro; and the Palácio das Artes, Belo Horizonte.