Vasszentmihályi völgyhíd, Road bridge in Vasszentmihály, Hungary

The Vasszentmihályi völgyhíd is a continuous ten-span road viaduct on the M8 motorway, carrying a 2×1 lane road at a design speed of 110 km/h. Its steel main girders form a composite deck about 574 m long, curving in plan to follow the motorway's arc. It crosses the valley of the Vörös-patak north of Vasszentmihály.

Planning for the Körmend–Szentgotthárd border section began with a 2010 environmental and heritage impact study by Mott MacDonald Magyarország and VIAMED 2002. The environmental permit was issued on 14 February 2013 for the KE-B1m-A2m-A3m alignment, and the NIF signed a design contract with the UNITEF-FŐMTERV-UTIBER-UVATERV consortium on 7 November 2013. Construction started on 8 March 2018; pylon foundations were laid in 2019 and the 575-metre steel structure was launched westwards from an assembly yard on the eastern hillside, finishing on 11 May 2020. The bridge opened to traffic in 2021.

The viaduct carries the M8 motorway past Vasszentmihály on the route between Körmend and the Austrian border, where it is planned to link with Austria's S7. Its 575-metre steel structure was pushed westwards from an assembly yard on the eastern hillside over nearly a year, a method local residents could follow as it advanced across the Vörös-patak valley.

The viaduct carries the M8 motorway at the 179+929 km mark, bypassing Vasszentmihály to the north; there is no pedestrian or cycle access, so it is seen only in passing by car. The 574 m steel structure curves with the roadway, and the ten concrete pylons are visible from the surrounding hillsides.

The 575-metre steel structure was pushed westwards from an assembly yard on the eastern hillside, a move completed on 11 May 2020 after almost a year. The deck is a continuous composite structure with ten spans, curving to follow the alignment of the road.