Spean Thma, Stone bridge in Angkor region, Cambodia.

Spean Thma is a stone bridge in the Angkor region with fourteen narrow arches constructed from sandstone blocks. The structure spans what was once a waterway and demonstrates the technical skill of ancient Khmer builders.

Spean Thma was built on the former course of the Siem Reap River between Angkor Thom and the Eastern Baray. It was probably rebuilt after the Khmer period, around the 15th century, using many reused sandstone blocks. It is one of the few Khmer Empire-era bridges to survive to the present day.

The Khmer name Spean Thma means "stone bridge". The 14 arches, each 1.10 m wide, are built from reused sandstone blocks, probably after the Khmer period around the 15th century. Similar bridges survive at Spean Memai in Angkor and at Spean Praptos on the road to Beng Mealea, which has 25 arches.

Spean Thma stands west of Ta Keo, on the old course of the Siem Reap River between Angkor Thom and the Eastern Baray. Visitors reach it on foot or by bicycle along the paths of the Angkor site, and the 14 arches, each 1.10 m wide, are best seen from the side rather than from the deck.

Spean Thma's sandstone blocks were largely reused from earlier Khmer monuments, which is why the bridge is dated to a rebuilding around the 15th century rather than to the Angkor period itself. The same model appears elsewhere in the former empire, notably Spean Praptos on the road to Beng Mealea, which has 25 arches.