Pernod Fils (French pronunciation: [pɛʁnoˈfis]) was the most popular brand of absinthe throughout the 19th century until it was banned in 1915. During the Belle Époque, the Pernod Fils name became synonymous with absinthe, and the brand represented the de facto standard of quality by which all others were judged.

The brand's roots can be traced as far back as the 1790s. According to legend, it was during this time in Neuchâtel, Switzerland that Dr. Pierre Ordinaire created a distilled patent medicine that would represent the earliest origins of the drink. The recipe then came into the hands of Henri Louis Pernod through the means of a business deal, and in 1797, he and Daniel Henri Dubied opened the first absinthe distillery in Couvet, Switzerland.

Pernod later built a larger distillery in Pontarlier, France in 1805. This set the stage that would cause the sleepy community of Pontarlier to eventually emerge as the home of twenty-eight commercial absinthe distilleries, and the world's center of absinthe production.