Papp is a Hungarian surname. It can refer to:

• Daniel S. Papp, President of Kennesaw State University
• Gustáv Papp (1919–1997), Slovak operatic tenor
• Josef Papp (c. 1933 – 1989), Hungarian-American engineer accused of creating a hoax
• Joseph Papp (1921–1991), American theatrical producer and director
• Joseph M. Papp (born 1975), American professional cyclist
• Krisztina Papp (born 1982), Hungarian long distance runner
• László Papp (1926–2003), Hungarian boxer and three-time Olympic champion
• László Papp (wrestler) (1905–1989), Hungarian wrestler and 1928 Olympic silver medalist
• Paul Papp (born 1989), Romanian footballer of Hungarian origin (Pál Papp)
• Robert J. Papp, Jr., Commandant of the United States Coast Guard and admiral

4'-Aminopropiophenone (para-aminopropiophenone or PAPP) is a chemical compound. It is highly toxic, and can cause injury or death upon physical contact or inhalation of fumes.