The workshop was due to take place at 5pm on the museum’s fanpage.
The museum said anyone who wanted to try making a bow at home should have red and white wool to hand.
Poland's Flag Day is a relatively new tradition - it was established in 2004.
In another initiative to mark the day, people across the country are being encouraged to display a red-and-white flag in front of their home, on a balcony or in their workplace, take a photo and share it on social media along with the hashtag #mojaflaga (#myflag).
The Warsaw Uprising by Polish fighters in 1944 was the largest military operation by any resistance movement in Europe against the continent's Nazi German occupiers during World War II.
(pk)
Source: Warsaw Uprising Museum