This list is based on the CIA World Factbook (when no citation is given) or other authoritative third-party sources (as cited). Based on data from EIA, at the start of 2021, proven gas reserves were dominated by three countries: Iran, Russia, and Qatar.
There is some disagreement on which country has the largest proven gas reserves. Sources that consider Russia in possession of the world's largest proven reserves include the US CIA (47,600 cubic kilometers), the US Energy Information Administration (EIA) (49,000 km<sup>3</sup>), and OPEC (48,810 km<sup>3</sup>). However, BP credits Russia with only 32,900 km<sup>3</sup>, which would place it in second place, slightly behind Iran (33,100 to 33,800 km<sup>3</sup>, depending on the source).
Due to constant announcements of shale gas recoverable reserves, as well as drilling in Central Asia, South America, Africa, and deepwater drilling, estimates are updated frequently. Since 2000, some countries, notably the US and Canada, have seen large increases in proven gas reserves due to development of shale gas, but shale gas deposits in most countries are yet to be added to reserve calculations.
Note: <big>*</big> indicates that the linked article is about natural gas production in the country or territory specifically, such as natural gas in Russia.
Comparison of proven natural gas reserves from different sources (cubic kilometers, as of 31 December 2014/1 January 2015)