Newborough (Welsh: Niwbwrch) is a village in the southern corner of the Isle of Anglesey in Wales. It is a part of the Bro Aberffraw electoral ward; to the northwest is Aberffraw, and to the northeast is Llanfairpwll. There is a church in the village, a primary school, and a public institute. Nearby is the Newborough Warren, a forest, beach, and public nature reserve.

Until 1984 it was a community. Today it is part of Rhosyr.

In medieval Gwynedd, Rhosyr was the royal demesne (Welsh: maerdref) and seat of governance for the commote of Menai. The location was a residence of the Princes of Gwynedd. There is a ruined court building of Llys Rhosyr (Rhosyr court) on the outskirts of the present village of Newborough; the royal court (Welsh: llys brenhinol) dates from 1237 and was in use for less than a century. The building was the inspiration and model for the reconstruction of a court at St. Fagans Museum, Cardiff.

Newborough gained its current name when the town was founded by citizens of Llanfaes in eastern Anglesey. The inhabitants were evicted in 1294 from east Anglesey to the west of the island by Edward I, to promote the new port of Beaumaris. The town was established as a "new borough" and gained its charter in 1303. Before the changes, the town was called Rhôs Vair. The charter was renewed by successive kings between the 14th and 19th centuries. During the age of Edward I (c. 1300), the town was promoted to the status of a corporation giving it a guild mercatory amongst other privileges, this status was confirmed once more during the reign of Edward III (first year of his reign, 1327), King of England. During the later part of this period, the town's population was around 93 houses around the royal manor. The Crown of England had a steward in this district who received a salary of 10 pounds per year. The court at Llys Rhosyr was still in use during this period, as it was noted that repairs were being done to the buildings. Also, during the 14th century, one of the leading Welsh poets of the Middle Ages, Dafydd ap Gwilym wrote a cywydd praising Newbourough for its generous hospitality, especially towards poets, describing it as both a sanctuary and a place of joyful abundance, symbolised through vivid images of wine, mead, and song.

During the medieval period, the local landed gentry in the royal borough had appointed an individual to the role of a Burgess, that person was given privileges from the Crown and would negotiate the Royal charter with the King of England in his parliament. Around the year 1489, during the reign of Henry VII of England, the county of Anglesey's court sessions (assizes) were moved to the town after 250 years in Beaumaris Castle, thus giving Newborough a member of parliament and making it the county town of Anglesey. It was Richard ap Rhydderch ap Myfyrian who represented Newborough in British Parliament during the reign of Henry VIII, and John ap Robert Llwyd during the reign of Edward VI. Then in 1550, the main court of Anglesey and all related county business was returned to Beaumaris.

Newborough's warren was home to a thriving marram grass industry; this grass was used to produce matting, nets, and rope. In 1814, Newborough's status as a Royal chartered borough of King George III was abolished after the resignation of the town mayor. The ending of the town's charter affected the people negatively and forced the closure of common land for grazing animals, and the town fell into a state of "severe deprivation", and the land was taken by the crown. The neighbouring town of Llanddwyn was incorporated into Newborough. During those years, a famous resident was John Morgan, a blind musician who played the crwth in the village.

In the village is St Peter's Church. The place of worship dates from the 14th century, with additions in the 15th and 16th centuries. The building was restored in 1850 and extended in 1886.

In 2019, the village opened a new Welsh-speaking primary school, Ysgol Santes Dwynwen.