A teaspoon (tsp.) is an item of cutlery. It is a small spoon that can be used to stir a cup of tea or coffee, or as a tool for measuring volume.^[1][2] The size of teaspoons ranges from about 2.5 to 7.3 mL (0.088 to 0.257 imp fl oz; 0.085 to 0.247 US fl oz). For cooking purposes and dosing of medicine, a teaspoonful is defined as 5 mL (0.18 imp fl oz; 0.17 US fl oz), and standard measuring spoons are used.^[3]

A teaspoon is a small spoon suitable for stirring and sipping the contents of a cup of tea or coffee, or adding a portion of loose sugar to it. These spoons have heads more or less oval in shape. Teaspoons are a common part of a place setting.

Teaspoons with longer handles, such as iced tea spoons, are commonly used also for ice cream desserts or floats. Similar spoons include the tablespoon and the dessert spoon, the latter intermediate in size between a teaspoon and a tablespoon, used in eating dessert and sometimes soup or cereals. Much less common is the coffee spoon, which is a smaller version of the teaspoon, intended for use with the small type of coffee cup.^[4] Another teaspoon, called an orange spoon (in American English: grapefruit spoon), tapers to a sharp point or teeth, and is used to separate citrus fruits from their membranes. A bar spoon, equivalent to a teaspoon, is used in measuring ingredients for mixed drinks.

A container designed to hold extra teaspoons, called a spooner, usually in a set with a covered sugar container, formed a part of Victorian table service.

The teaspoon is a European invention.^[6] Small spoons were common in Europe since at least the 13th century. These special spoons were introduced almost simultaneously with tea and coffee^[6] (Pettigrew points to use in the mid-17th century^[7]). Originally teaspoons were exotic items, precious and small, resembling the demitasse spoons of the later times.^[6] Also used for coffee, these spoons were usually made of gilt silver, and were available with a variety of handle shapes: plain, twisted, decorated with knobs,^[7] also known as knops, hence the knop-top name for such spoons.^[8] Widespread use and modern size date back to the Georgian era.^[6] The teaspoon is first mentioned in an advertisement in a 1686 edition of the London Gazette,^[9][10] teaspoons, probably of English origin, are present on the 1700 Dutch painting by Nicholas Verkolje, "A Tea Party".^[11]

A special dish for resting the teaspoons, a "spoon boat", was a part of the tea set in the 18th century.^[12] At that time, the spoons were playing important role in the tea drinking etiquette: a spoon laid "across" the teacup indicated that the guest did not need any more tea, otherwise, the hostess was obligated to offer a fresh cup of tea, and it was considered impolite to refuse the offering.^[13][14] Pettigrew reports that sometimes the spoons were numbered to make it easier to match the cups with the guests after a refill.^[13]

In some countries, a teaspoon (occasionally teaspoonful) is a cooking measure of volume, especially widely used in cooking recipes and pharmaceutic medical prescriptions. In English it is abbreviated as tsp. or, less often, as t., ts., or tspn.. The abbreviation is never capitalized because a capital letter is customarily reserved for the larger tablespoon ("Tbsp.", "T.", "Tbls.", or "Tb.").^[15]

The household teaspoons provide very bad approximations of any unit of measure. In a small-scale research, Falagas et al. found out that the volume of liquids inside different teaspoons varies almost three times, between 2.5 and 7.3 ml (0.088 and 0.257 imp fl oz; 0.085 and 0.247 US fl oz).^[16]

• Bar spoon
• Caddy spoon, a specialized spoon used for taking dried tea out of a storage container
• Cooking weights and measures
• Dessert spoon
• Tablespoon