Barthout van Assendelft (born around 1440 - died after 1502) was a Dutch Grand Pensionary.
The origins of Barthout van Assendelft are unclear.
He might have been related to Barthout van Assendelft Willemsz, Lord of Vlieland and Veenhuizen, steward of Philip the Good and alderman of Haarlem, who was married to Yde van Swieten.
He obtained his doctorate in law from the University of Ferrara (Italy) in 1462.
The coat of arms of the Van Assendelft family consisted of a passant horse in argent on a field of red (in het rood een stappend zilveren paard).