It is from the Low German form of the anthroponymic name Landberht from the Old High German land "(home) land" and beraht "bright".
[3] variant forms include: Lamberty, Lambertot, Lamberton.
[4] As of 2014, 36.1% of all known bearers of the surname Lambert were residents of the United States (frequency 1:3,039), 26.4% of France (1:765), 8.5% of England (1:1,983), 7.3% of Canada (1:1,533), 4.9% of Belgium (1:705), 2.8% of Australia (1:2,604), 2.4% of Nigeria (1:22,741), 1.5% of Germany (1:16,231) and 1.4% of South Africa (1:12,113).
In Belgium, the frequency of the surname was higher than national average (1:705) in Wallonia (1:296).
In France, the frequency of the surname was higher than national average (1:765) in the following regions:[5]