Exact details of what happened are unclear, but according to The New York Times, the Americans, some of whom are children, were abducted by an armed gang outside an orphanage in Haiti's capital, Port-au-Prince.
Authorities say the abductees were on a bus that would take them to the city's airport.
During the summer, Haiti has become increasingly unstable in connection with the assassination of President Jovenel Moïse and a powerful earthquake took thousands of lives.
According to the news agency AFP, more than 600 kidnappings were carried out in the country during the first nine months of the year, compared with 231 during the same period last year.