The Foxton Branch was a railway line in New Zealand. It began life as a tramway, reopened as a railway on 27 April 1876, and operated until 18 July 1959. At Himatangi there was a junction with the Sanson Tramway, a line operated by the Manawatu County Council that was never upgraded to the status of a railway.

At the mouth of the Manawatū River, the settlement of Foxton was seen in the 1860s as a possible port for the Manawatu region. Roads often became treacherous and impassable in bad weather, and as the Manawatū River was not navigable far inland, a more dependable route than the roads was necessary so that the region could receive imports and export its products, particularly timber. Due to poor financial conditions at the time, a tramway built with wooden rails rather than a railway was proposed in 1865 as a cost-effective mode of transport. Not even this was affordable at the time, and it was not until Julius Vogel announced his "Great Public Works" policy in 1870 that construction was finally approved.

As planned in 1865, the line was built as a wooden-railed tramway, with construction commencing in 1871. On 20 August 1872, a steam locomotive constructed by the Dunedin firm of Messrs R. S. Sparrow and Co. was delivered and operated on the completed portion of tramway; this was the first New Zealand-built locomotive to run.

The line was completed to Palmerston North on 25 July 1873, a distance of 40 kilometres, and soon proposals were made to extend it to Wanganui. By 1874 the inadequacies of wooden rails were becoming apparent, and after an attempt at relaying the line with iron rails in February 1875 did not provide the durability required, the decision was made to relay the line with steel rails to railway standards. The land through which the line ran was generally flat, with the Oroua River the only serious obstacle. It was crossed with a 56-metre-long (184 ft) bridge. The line was formally re-opened as a railway on 27 April 1876.

In 1885, the Sanson Tramway connected to the branch at Himatangi. The tramway closed in 1945.

In 1886 the Wellington and Manawatu Railway Company (W&MR), the private company established to build the "West Coast" Wellington–Manawatu Line due to the government's inaction, opened from Wellington to the Foxton line at Longburn, near Palmerston North. The government's original plan had been to extend the Foxton line down to Wellington, but the W&MR announced in 1881 that it would follow the most direct route to Palmerston North, bypassing Foxton. The Foxton line effectively became a branch line from Longburn, though it remained the southern terminus of the government railway until 1908 when the WM&R was purchased and incorporated in the North Island Main Trunk railway linking Wellington and Auckland.

The following stations were on the Foxton Branch, with the distance from the junction at Longburn in brackets:

The line was very important for its first 12 years. Northbound freight and passengers from Wellington came up the west coast via ship and transferred to the railway in Foxton, and the town was served by express trains. When the WMR's line opened, traffic to Foxton dropped so markedly that services were slashed to run on alternate days, though daily trains were later restored. Passenger ships between Wellington and Foxton disappeared overnight. Most freight also used the new line, but the government railways did not wish to utilise a competitor's service and continued to ship railway coal in via Foxton instead of using W&MR. The flax trade in the region also continued to use Foxton as a harbour and provided traffic for the line.