The flag of Terschelling is more than just a recognisable symbol; it tells the story of the island's unique nature and culture. Since its official introduction on 27 October 1961, the flag has stood out with its five colourful stripes, directly reflecting the island's beauty. The colours are based on the Coat of Arms of Terschelling but also hold poetic significance. Gerrit Knop wrote a rhyme in 1932 about the colours of the flag:

Red are the clouds,
Blue is the sky,
Yellow are the dune grasses,
Green is the grass,
White is the sand,
These are the colours of Schellingerland.

The Coat of Arms of Terschelling is a striking and colourful symbol with a rich history. The first known mention of the Coat of Arms dates back to the 16th century on a map titled Beschrijvinghe van Schellingerland by Sybrandt Hanssen. The map depicts a silver shield with a green tree. To the left (heraldic right) is a red lion, and to the right (heraldic left) is a blue dragon.
A century later, the Coat of Arms appeared mirrored on a collection box in Midsland, maintaining the same colours. In 1666, a version was recorded where the dragon had a golden mane and head, resembling the Coat of Arms of the Van der Schelling family.
Over the years, the depiction of the Coat of Arms varied across locations and periods. In 1596, Oosterend used a seal with only the animals and no tree. In the 18th century, Midsland used a seal without animals. In 1661, a seal depicted the lion standing on the dragon, with no tree present.

The colours of the tree and lion remained consistent over time, but the dragon’s colour varied. It was depicted in green, red, or blue in different versions. In 1963, the Fryske Rie foar Heraldiek recommended making the dragon blue for aesthetic reasons. A proposal for a two-coloured dragon was rejected by the High Council of Nobility. Consequently, the Coat of Arms was updated with a solid blue dragon and golden fruits in the tree.

The first official Coat of Arms of Terschelling, granted by the High Council of Nobility on 26 June 1816, was described as follows:
"Azure (blue), bearing a tree, to the right of which stands a sea monster and to the left a standing dog, all in gold."

On 27 September 1963, Terschelling received a renewed Coat of Arms with the following description:
"Argent (silver), a tree in vert (green) with golden fruits, standing on a vert base, accompanied on the dexter side by a rampant lion in gules (red) and on the sinister side by a rampant dragon in azure (blue), both clasping the tree trunk with their claws. The shield is surmounted by a golden crown of three leaves and two pearls."

This modern Coat of Arms features a silver background with a green tree, golden fruits, and a green base. To the left is a red rampant lion, and to the right is a blue rampant dragon. Both animals grasp the tree trunk with their claws. The shield is crowned with a golden crown of three leaves and two pearls.