Data compiled by the Armed Conflict Location and Event Data project (ACLED) reveals that at least 11 Americans were killed while participating in demonstrations in 2020.
Another two people were killed after taking part in pro-Trump rallies, according to ACLED. Lee Keltner was shot after reportedly slapping a security guard at a "patriot rally", while Aaron Danielson was allegedly shot by a left-wing protester who claims he acted in self-defence.
Most of the protesters killed this year were shot to death.
Others were killed when cars drove or rammed through crowds of Black Lives Matter protesters.
At least 14 more Americans were killed in incidents linked to wider political unrest.
They include seven people shot during alleged looting, two law enforcement officers killed by an alleged anti-government extremist, and an eight-year-old girl shot dead in Georgia.
However, ACLED said that reports of dozens of deaths at the height of the Black Lives Matter protests this summer were found to be unconnected to the demonstrations.
The more than 9,000 anti-racist protests that took place across the country were overwhelmingly peaceful, ACLED said.
ACLED's figures do not include killings of Black Americans by the police that sparked protests, such as those of Floyd and Breonna Taylor.