Langisjór

{{Short description|Lake in Iceland}}

{{no footnotes|date=August 2021}}

{{Infobox body of water

| name = Langisjór

| image = Langisjor_2006.jpg

| caption = in summer

| image_bathymetry =

| caption_bathymetry =

| location =

| coords = {{coord|64|11|N|18|15|W|region:IS_type:waterbody|display=inline,title}}

| type =

| inflow =

| outflow =

| catchment =

| basin_countries = Iceland

| length = {{convert|20|km|abbr=on}}

| width = {{convert|2|km|abbr=on}}

| area = {{convert|26|km2|abbr=on}}

| depth =

| max-depth = {{convert|75|m|abbr=on}}

| volume =

| residence_time =

| shore =

| elevation = {{convert|670|m|abbr=on}}

| islands =

| cities =

| pushpin_map = Iceland

| pushpin_label_position =

| pushpin_map_alt = Location of Langisjór in Iceland.

| pushpin_map_caption =

| website =

| reference =

}}

Langisjór ({{IPA|is|ˈlauɲcɪˌsjouːr̥|audio=Langisjór pronunciation.ogg}}) is a lake in the western part of Vatnajökull National Park, Iceland. It is around 20 km in length and up to 2 km wide, with a total surface area of about {{convert|26|km2|abbr=on}} and a depth of 75m at its deepest point.

The lake is situated rather far from civilisation at the south-western border of Vatnajökull at an altitude of 670 m above sea level. Environmental campaigners have expressed concern at government plans to site an industrial dam on the lake.