Harvard professor Latanya Sweeney found that searches for black-related names on Google and related websites were more commonly met with information on criminal activity.
For example, a Google search for the name "Trevon Jones" was more likely to attract personalised ads for public records, including "Trevon Jones, Arrested?...", with a link to a website for performing checks on criminal records.
The study looked at search on Google.com and also the search function on Reuters.com, which displays Google advertising.
Professor Sweeney said that names more commonly associated with black people, such as DeShawn, Darnell and Jermaine, were 25% more likely to generate ads suggestive of arrest.
By contrast, searches for names generally assigned at birth to whites, such as Geoffrey, Jill and Emma, generated more neutral ad suggestions.
She added that websites such as Google "may now have to think about societal consequences like structural racism in the technology they design".
But Google insisted that it "does not conduct any racial profiling".
"We also have an 'anti' and violence policy which states that we will not allow ads that advocate against an organisation, person or group of people," Google told BBC News.
"It is up to individual advertisers to decide which keywords they want to choose to trigger their ads."