Cistercian Abbey at Whitland, Carmarthenshire, Wales was founded in 1140 under the patronage of Bernard, bishop of St. Davids (1115-1148). It was the first of four houses in Wales to be colonised directly from Clairvaux, and was destined to be the mother-house of most of the abbeys founded in the second half of the 12th century in the central and northern parts of Wales. The community of monks first arrived in West Wales in 1140 and by 1144 had settled at Little Trefgarn near Haverfordwest. Whitland took pride of place amongst the early Cistercian abbeys of south Wales and was from the first a house of the native Welsh in which members of the chief families took the habit and became abbots. Whitland established three colonies of monks within thirty years of existence: Cwmhir (1143), Strata Florida (1164) and Strata Marcella (1170). By the 15th century the abbey supported 100 monks. In 1151 the monks at Little Trefgarn moved to a more suitable site at Whitland. From approximately 1165 patronage of Whitland was acquired by Prince Rhys ap Grufford (d. 1197). Under his patronage the community prospered and by the 13th century the abbey had extensive landholdings organised around it's 17 grange. In the following decades Whitland sent out a further two colonies to establish daughter-houses at Comber (1199) and Tracton (1224).

Whitland supported Welsh independence and in 1257 Stephen Bauzan, Nicholas lord of Cemais, Patrick de Chaworth lord of Kilwelly and lord of Carew, accompanied by a band of knights, invaded Whitland Abbey, belaboured the monks, stripped the lay-brethren, and killed the abbey servants. When the attackers left they took with them Whitland's horses and valuables, except those in the church. The abbey also suffered great damage during the Welsh wars of King Edward I. It is known that a royal inquest during the reign of Edward I had acknowledged a claim for £260 by way of compensation. However, nothing was ever paid to the abbey and it has been suggested that Whitland forfeited its right of compensation by its overt assistance to the Welsh during the years of conflict. Following these events Whitland began to decline in wealth and at the time of the Dissolution the net annual income of the abbey was valued at £135. In 1536 Abbot William Thomas avoided the closure of his abbey by proffering the vast sum of £400. The abbey survived for only three more years and was finally dissolved with the larger monasteries in February 1539.

Little remains of the abbey today, save some fragments of the abbey church. However, the plan of the precinct is visible in outline, depending how long the grass is, but it can only be viewed from the pubic road.

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