Seidel

• Seidel (crater), after Philipp Ludwig von Seidel
• Seidel Band Instrument Company
• Hanns-Seidel-Foundation, after Hanns Seidel
• Gauss–Seidel method, after Philipp Ludwig von Seidel
• Sidell

Seidel is the surname of:

• Ed Seidel, a computer scientist and physicist
• Emil Seidel, Socialist mayor of Milwaukee
• Erik Seidel, American poker player
• Frederick Seidel, American poet
• Hanns Seidel, German politician
• Heinrich Seidel (1842–1906), German engineer and writer
• Henry Seidel Canby
• Jaap Seidel (1919-2001), Dutch mathematician
• James Seidel (Born 1966) American tire entrepreneur
• Philipp Ludwig von Seidel (1821–1896), German mathematician, optician and astronomer
• Mike Seidel, meteorologist
• Silvia Seidel (born 1969), German actress
• Wolfgang Seidel, German autoracer

Seidl is the surname of:

• Anton Seidl (1850–1898), Hungarian conductor
• Gabriel von Seidl (1848-1913), German architect
• Johann Gabriel Seidl (1804-1875), Austrian archaeologist, lyricist, narrator and dramatist
• Otto Seidl (* 1931), until 1998 vice-president of the German Supreme Court
• Siegfried Seidl (1911-1947), Commander of the concentration camp at Theresienstadt
• Ulrich Seidl (* 1952), Director, screen writer and producer
• Florian Seidl (* 1979), Vehicle Designer

Seydel is the surname of:

• Christian August Seydel, founder of C. A. Seydel Söhne, a harmonica factory
• Anton Gilbert Edler von Seydel, Honorary Citizen of Vienna
• Karl Theodor Seydel, former mayor of Berlin