Blendecques (French pronunciation: [blɑ̃dɛk]; West Flemish: Blendeke) is a commune in the Pas-de-Calais department in the Hauts-de-France region in northern France.

The town is situated 3 miles (5 km) south of Saint-Omer, at the junction of the D77, D210 and D211 roads. The river Aa flows through the commune.
The town has a football team and a basketball team.

Historical population

Year	Pop.	±% p.a.
1968	4,431	—
1975	5,014	+1.78%
1982	5,338	+0.90%
1990	5,210	−0.30%
1999	5,186	−0.05%
2007	5,090	−0.23%
2012	5,205	+0.45%
2017	5,002	−0.79%
Source: INSEE

• Alfred Machin, filmmaker
• Hugo Vandermersch, footballer

• The nineteenth-century church of St. Gilles.
• The Chapelle de Soyecques.
• The eighteenth-century Château de La Garenne.
• Another Château of the 19th century.
• The abbey of Sainte-Colombe, dating from the twelfth century.
• The remains of some old watermills and lime-kilns.

• Audomarois
• Communes of the Pas-de-Calais department

• Football Club Patriote of Blendecques Archived 2009-02-14 at the Wayback Machine (in French)