The Royal Welch Fusiliers (Welsh: Ffiwsilwyr Brenhinol Cymreig) was a line infantry regiment of the British Army, and part of the Prince of Wales's Division, that was founded in 1689; shortly after the Glorious Revolution. In 1702, it was designated a fusilier regiment and became the Welch Regiment of Fusiliers; the prefix "Royal" was added in 1713, then confirmed in 1714 when George I named it the Prince of Wales's Own Royal Regiment of Welsh Fusiliers. In 1751, after reforms that standardised the naming and numbering of regiments, it became the 23rd Regiment of Foot (Royal Welsh Fuzileers). In 1881, the final title of the regiment was adopted.

Welsh is a Celtic language of the Brittonic subgroup that is native to the Welsh people. Welsh is spoken natively in Wales, by some in England, and in Y Wladfa.