Low-alcohol beer (also called non-alcoholic or NA beer, small beer, small ale, or near-beer) is beer with very low or no alcohol content. Most low-alcohol beers are lagers, but there are some low-alcohol ales.

In the United States, beverages containing less than 0.5% alcohol by volume (ABV) were legally called non-alcoholic, according to the now-defunct Volstead Act. Due to its very low alcohol content, non-alcoholic beer may be legally sold to minors in most American states.

In the United Kingdom, the following definitions apply by law (correct as of May 2007):

• No alcohol or alcohol-free: not more than 0.05% ABV
• Dealcoholised: over 0.05% but less than 0.5% ABV
• Low-alcohol: not more than 1.2% ABV

In the rest of the European Union, beer must contain no more than 0.5% ABV if it is labelled "alcohol-free".

Although labeled as non-alcoholic, some beers may still contain small amounts of alcohol; as a result, some American states prohibit their sale to minors and even to young adults. In one state (Pennsylvania) persons must be 21 years of age or older to even consume non-alcoholic beer, or they will be cited for underage drinking.

• Wisconsin law does not regulate non-alcoholic beer (less than 0.5% ABV), and it can be purchased without any age restrictions.
• According to Michigan law, persons must be 18 or older to purchase "non-alcoholic beer" within the state.

In countries where alcohol advertising is forbidden or limited, non-alcoholic versions of popular brands of alcoholic beverages have been created for the purpose of advertisement.