The Hasli region (also called Oberhasli, or Haslital "Hasli valley") is a historical Landvogtei or Talschaft in the Bernese Oberland, Switzerland, bordering on the cantons of Obwalden, Uri and Wallis. The local dialect is of the Highest Alemannic variety.
From 1833 to 2009, Hasli was incorporated as the Oberhasli district, the easternmost of the 26 districts of the Canton of Bern, bordering the district of Interlaken to the west. Since 2010, Oberhasli and Interlaken have been administratively united as the region of Interlaken-Oberhasli.
With its area of 551 km², it is larger than the canton of Basel-Landschaft. It consists of the six municipalities of Gadmen, Guttannen, Hasliberg, Innertkirchen, Meiringen and Schattenhalb, with a total population of just below 8,000, corresponding to a population density of less than 15/km2 (compared to a Swiss average of 181/km2), due to a significant portion of the area of Oberhasli being uninhabitable High Alps.
The name Haslital is first attested in 1234. The prefix Ober- ("Upper Hasli") first appears in the 16th century for disambiguation with Hasle bei Burgdorf, Oberhasli is in official use since 1798. The origin of the name is likely Old High German hasal "hazel".