The winning image, by Hadi Asadi from Iran, shows the US president wearing a jacket of dollar bills and with burning yellow hair.
Organisers of the Trumpism exhibition in Tehran have held similar contests in the past on themes including the Islamic State group and the Holocaust.
This year's logo is based on the Nazi emblem, with a T instead of a swastika.
It encouraged many comparisons between the US president and Nazism.
"The 'ism' in Trumpism is a reference to racism and Nazism," organiser Masuod Shojai Tabatabaei told the Associated Press.
"Many believe his remarks are similar to Hitler. He has had a bad attitude toward media [and] refugees."
The group's Holocaust-themed cartoon contest last year drew condemnation from Israeli Prime Minister Binyamin Netanyahu.
But organisers said it was designed to highlight Western double standards on free speech rather than cast doubt on the Nazi genocide.
Others depictions in this year's competition drew on Mr Trump's promises to build a wall on the US-Mexican border as well as violence against women and attacks on the media.
Entrants include several cartoonists from the US and the UK.
American Clayton Jones's artwork shows the cover of two copies of Time magazine, one with President Trump's picture and the other with Adolf Hitler.
They are both are portrayed as Time's Person of the Year with Mr Trump telling Hitler: "It is a great honor" and in return Hitler replies "Ja."
Hundreds of cartoonists from around the world have taken part in a competition in Iran attacking Donald Trump.