Pontarddulais (Welsh pronunciation: [pɔntarˈðɨːlais]), also spelled Pontardulais (Welsh pronunciation: [pɔntarˈdɨːlais]), is a town and community in Swansea, Wales. It is 10 miles (16 km) northwest of the city centre. It is in the Pontarddulais ward of the City and County of Swansea Council. Pontarddulais adjoins the village of Hendy in Carmarthenshire. The built-up population was 9,073.

An English translation of the name Pontarddulais is "Bridge over the Dulais", with Dulais meaning "black stream", probably due to its course through coal measures. The earlier name of Pontaberdulais referred to a dismantled 14th-century road bridge which carried the main highway between Swansea and Carmarthen over the River Loughor (Afon Llwchwr). The bridge was so named because of its position upstream of the mouth (aber) of the Dulais stream. This bridge was also known as Y Bont Fawr ("the big bridge"). The village that developed around this bridge took the shortened name of Pontardulais, also written incorrectly as Pontarddulais because of the assumption that the bridge was "over Dulais". The bridge also gave the town its nickname "Y Bont".

Most of the town lies within the parish of Llandeilo Tal-y-bont apart from the small section west of the bridge which lies in Llanedi parish. The bridge referred to in the name of Llandeilo Tal-y-bont (meaning "Saint Teilo's church at the end of the bridge") is not the same as that of Pontaberdulais. The church bridge was located near the old church on the earlier Roman road that crossed the river Loughor near Hendy. The medieval church of St Teilo was carefully dismantled stone-by-stone and reassembled in St Fagans National History Museum in Cardiff. Pontarddulais first gained attention in the wider world in 1843, during the Rebecca Riots, when rioters attacked the toll gate there, after crossing the bridge.

The path to industrialisation began in the early 19th century. In 1839 the railway arrived in the town when the Llanelli Dock Company built a line to transport anthracite coal from the Amman Valley to Llanelli. In 1866, a new line was built connecting Pontarddulais with Swansea which made the town an important railway junction. Pontarddulais was transformed from a rural settlement into an industrial community during the years 1872 to 1910 when six tinplate works were established. The population expanded greatly during this period, as workers from nearby communities and as far afield as Italy moved in to find work in the tinplate industry.

A new single-span bridge was built beside Y Bont Fawr in 1938, and the old bridge was demolished at the end of the World War II. The 1950 saw another major transformation in Pontarddulais. New, modern tinplate works in nearby Trostre and Felindre rendered the old works obsolete. The local works were taken over by other enterprises and redeveloped as light industry. However, they did not replace all the jobs lost due to the closure of the local tin plate works. Some of the local people had to find work elsewhere. Light industry gradually began deserting Pontarddulais in the late 20th century, transforming the community into a dormitory village.

The town's schools are Pontarddulais primary school, Pontarddulais Comprehensive School (both English medium) and Bryniago School, a Welsh medium primary school.

Pontarddulais railway station is on the Heart of Wales Line, with trains to Swansea to the south and Shrewsbury to the north. The A48 traverses the town as St Teilo Street and Bolgoed Road. Junction 48 of the M4 Motorway serves Pontarddulais.

Pontarddulais hosts many cultural events throughout the year, including Pontarddulais and Hendy carnival, which makes its way from Hendy Industrial Estate to Coed Bach Park in Pontarddulais on the last Saturday of June. Also held in the town is Pontarddulais Show, an agricultural show held on August Bank Holiday, and the Classic Car and Motor Show, held in September, both of which take place at Pontarddulais Agricultural Show Ground.