The Beqaa Valley (Arabic: وادي البقاع, romanized: Wādī l-Biqā‘, Lebanese Arabic: [bʔaːʕ]; also romanized as Bekaa, Bekai, Biqâ, and Becaa) is a fertile valley in eastern Lebanon and its most important farming region. Industry, especially the country's agricultural industry, also flourishes in Beqaa. The region broadly corresponds to the Coele-Syria of classical antiquity.

The Beqaa is located about 30 km (19 mi) east of Beirut. The valley is situated between Mount Lebanon to the west and the Anti-Lebanon mountains to the east. It is the northern continuation of the Jordan Rift Valley, and thus part of the Great Rift Valley, which stretches from Syria to the Red Sea. Beqaa Valley is 120 kilometres (75 mi) long and 16 kilometres (9.9 mi) wide on average. It has a Mediterranean climate of wet, often snowy winters and dry, warm summers.

The region receives limited rainfall, particularly in the north, because Mount Lebanon creates a rain shadow that blocks precipitation coming from the sea. The northern section has an average annual rainfall of 230 millimetres (9.1 in), compared to 750 millimetres (30 in) in the central valley. Nevertheless, two rivers originate in the valley: the Orontes (Asi), which flows north into Syria and Turkey, and the Litani, which flows south and then west to the Mediterranean Sea.

From the 1st century BC, when the region was part of the Roman Empire, the Beqaa Valley served as a source of grain for the Roman provinces of the Levant. Today the valley makes up 40 percent of Lebanon's arable land. The northern end of the valley, with its scarce rainfall and less fertile soils, is used primarily as grazing land by pastoral nomads. Farther south, more fertile soils support crops of wheat, maize, cotton, and vegetables, with vineyards and orchards centered on Zahlé.

The valley also produces hashish and cultivates opium poppies, which are exported as part of the illegal drug trade.

In Baalbek, that is part of a valley to the east of the northern Beqaa Valley, there are evidence of continual habitation dating back almost 8000–9000 years. Ard Tlaili is a small tell mound with an archaeological site, located on a plain at the foot of the Lebanon Mountain, just 11 km (7 mi) northwest of Baalbeck, in the Beqaa Valley. It dates to around 5780-5710 BC and has the southernmost pottery belonging to the Halaf Culture.

Labweh is a village at an elevation of 950 metres (3,120 ft) on a foothill of the Anti-Lebanon Mountains in Baalbek District, Baalbek-Hermel Governorate, Lebanon, settled since the Neolithic period.

In the Middle Bronze IIA, the Beqa Valley was a highway between the regional power of Qatna in the north and its vassal Hazor in the south. The Beqaa valley was known as Amqu during the Bronze Age. The identity of the inhabitants is not known for certain, but the region was part of the Amorite Kingdoms of Amurru and Qatna. To the southwest of Baalbek was Enišasi, a city or city-state mentioned in the 1350-1335 BC Amarna letters correspondence, written by two rulers of the city Šatiya and Abdi-Riša.