The flag of Wales (Y Ddraig Goch, meaning 'the red dragon') consists of a red dragon passant on a green and white field. As with many heraldic charges, the exact representation of the dragon is not standardised and many renderings exist. The flag is not represented in the Union Flag.

The flag incorporates the dragon of Cadwaladr, King of Gwynedd, along with the Tudor colours of green and white. It was used by Henry VII at the Battle of Bosworth in 1485, after which it was carried in state to St Paul's Cathedral. The red dragon was then included as a supporter of the Tudor royal arms to signify their Welsh descent. It was officially recognised as the Welsh national flag in 1959. Several cities include a dragon in their flag design, including Cardiff, the Welsh capital.

The green and white stripes of the flag were additions by the House of Tudor, the Welsh dynasty that held the English throne from 1485 to 1603. Green and white are also the colours of another national emblem of Wales, the leek.

Although Henry VII recognised the red dragon upon its blessing at Saint Paul's Cathedral following his victory at Bosworth Field under the realm of 'England and Wales' in 1485, the United Kingdom would not recognise the flag's official status again until 1959,[1] despite the dragon being used by Romanised Celtic Britons since at least the fall of the Roman empire in 6th century AD.

The dragon of Wales was used by countless of Welsh rulers as a propaganda tool; to portray their links to the Arthurian legend, the title given to such rulers is Y Mab Darogan (The prophesied Son). The most notable native Welsh princes to use the dragon was Owain Glyndŵr & Henry Tudor, their dragons were significantly different in appearance, although despite them living 80 years apart, it is not known why they look dissimilar.

During the Tudor dynasty the red dragon was often depicted with a pizzle, an instrument which symbolises a generation in the male line which was important to promote the authenticity of the royal lineage, the current British royal family who are descendants of the Tudors continue to depict the Welsh dragon with a pizzle.