The pith helmet, also known as the safari helmet, salacot, sola topee, sun helmet, topee, and topi is a lightweight cloth-covered helmet made of sholapith. The pith helmet originates from the Spanish military adaptation of the native salakot headgear of the Philippines.

It was often worn by European travellers and explorers in the varying climates found in Southeast Asia, Africa, and the tropics, but it was also used in many other contexts. It was routinely issued to colonial military personnel serving in warmer climates from the mid-nineteenth to the mid-twentieth century. The headdress remains in use in several military services in the 21st century.

Typically, a pith helmet derives from either the sola or "pith" plant, Aeschynomene aspera, an Indian swamp plant, or from Aeschynomene paludosa. In the narrowest definition, a pith helmet is a type of sun hat made from the wood of the pith plant. However, pith helmet may more broadly refer to this style of helmet when made from any number of lightweight sun-shading materials, such as cork wood, rattan or fiber. It was designed to shade the wearer's head and face from the sun.

The origin of the pith helmet is the traditional Filipino headgear known as the salakot (Spanish salacot, a term still also used for pith helmets). They are usually dome-shaped or cone-shaped and can range in size from having very wide brims to being almost helmet-like. The tip of the crown commonly has a spiked or knobbed finial made of metal or wood. It is held in place by an inner headband and a chin strap. These were originally made from various lightweight materials like woven bamboo, rattan, and calabash; sometimes inlaid with precious metals, coated with water-proof resin, or covered in cloth.

Salacots were used by native Filipino auxiliaries in the Spanish colonial military as protection against the sun and rain during campaigns. They were adopted fully by both native and Spanish troops in the Philippines by the early 18th century. The military versions were commonly cloth-covered and gradually took on the shape of the Spanish cabasset or morion.

The salacot design was later adopted by the French colonial troops in Mainland Southeast Asia in the 19th century (who called it the salacco or salacot, a term also later applied to the native Vietnamese cone-shaped or disk-like nón lá) due to its effectiveness in protecting from damp and humid weather. French marines also introduced the early version of the salacot to the French West Indies, where it became the salako, a cloth-covered headgear still mostly identical to the Filipino salakot in shape. British and Dutch troops, and other colonial powers in nearby regions followed suit and the salacot became a common headgear for colonial forces in the mid-19th century.

While this form of headgear was particularly associated with the British Empire, all European colonial powers used versions of it during the late 19th and early 20th centuries. The French tropical helmet was first authorised for colonial troops in 1878. The Dutch wore the helmet during the entire Aceh War (1873–1904), and the United States Army adopted it during the 1880s for use by soldiers serving in the intensely sunny climate of the Southwestern United States. It was also worn by the North-West Mounted Police in policing North-West Canada, 1873 through 1874 to the North-West Rebellion and even before the stetson in the Yukon Gold Rush of 1898.

European officers commanding locally recruited indigenous troops, as well as civilian officials in African and Asian colonial territories, used the pith helmet. Troops serving in the tropics usually wore pith helmets. However, on active service, they sometimes used alternatives such as the wide-brimmed slouch hat worn by US troops in the Philippines and by British Empire forces in the later stages of the Boer War.