Jonas Slier

{{short description|Dutch artistic gymnast}}

{{Infobox gymnast

| name = Jonas Slier

| image =

| alt =

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| full_name =

| birth_date = {{Birth date|1886|03|22|df=yes}}

| birth_place = Amsterdam, Netherlands

| death_date = {{Death date and age|1942|11|05|1886|03|22|df=yes}}

| death_place = Oświęcim, Poland

| discipline = MAG

| country = Netherlands

| natlteam =

}}

Jonas Slier (22 March 1886 in Amsterdam – 5 November 1942 in Auschwitz concentration camp{{cite book|last1=Schaffer|first1=Kay |last2=Smith|first2=Sidonie |title=The Olympics at the Millennium: Power, Politics, and the Games|url=https://books.google.com/books?id=nMzYdZpk8qMC&dq=holocaust+%22After+the+games%22&pg=PA61|year=2000|publisher=Rutgers University Press|isbn=978-0-8135-2820-5|pages=60–62}}{{cite web |url=https://www.sports-reference.com/olympics/friv/lists.cgi?id=65 |archive-url=https://web.archive.org/web/20200417055433/https://www.sports-reference.com/olympics/friv/lists.cgi?id=65 |url-status=dead |archive-date=17 April 2020 |title=Olympians Who Were Killed or Missing in Action or Died as a Result of War |accessdate=24 July 2018 |work=Sports Reference}}) was a Dutch gymnast who competed in the 1908 Summer Olympics.{{cite web|url=https://www.olympedia.org/athletes/30756 |title=Jonas Slier |work=Olympedia |access-date=1 March 2021}}

Jonas Slier was part of the Dutch gymnastics team, which finished seventh in the team event. In the individual all-around competition he finished 96th. There is no evidence that another Jonas Slier, the uncle of Philip Slier was the athlete mentioned above.(Hidden Letters, Star Bright Books 2008, pp. 10, 47, 116, 159,160, 167 note 42 C).