International Heraldry Day is celebrated on 10 June. The celebration of this day began in 2013 at the initiative of Tomasz Steifer, a member of the International Association of Amateur Heralds.

June 10 is the day when in the year 1128 in Rouen, France, Geoffrey V Plantagenet was knighted by Henry I of England. During the ceremony he received a blue shield with six golden lions, which is considered probably the first granting of a coat of arms in history. Whether this coat of arms is the first in history is being debated by the heralds, but still this coat of arms and this specific act is taken as the occasion for celebrating heraldry.

In 2015 the International Heraldry Day got its own coat of arms with blazon: