A roof tile is a manufactured piece of hard-wearing material such as ceramic, stone, metal, or even glass.
The word tile is derived from the French word tuile, which is, in turn, from the Latin word tegula, meaning a roof tile composed of baked clay.
Less precisely, the modern term can refer to any sort of construction tile or similar object, such as rectangular counters used in playing games (see tile-based game).

In the past twenty years, the technology surrounding porcelain tile and glass tiles has become more efficient, allowing more mass production. Similarly, the invention of automated tile lines that use diamonds to cut and finish stone slabs into tiles has made stone tiles more available. This has allowed these tiles to move from being niche items into broader markets.

Made from renowned Ohio clays, Celadon Ceramic Slate is molded to the subtle surface textures of natural slate, then fired at temperatures exceeding 2,100°F to make it impervious to moisture, heat, fire and repeated freeze-thaw cycles. Compared with other slate alternatives, tests prove that Celadon Ceramic Slate is up to four times stronger, 10 times stiffer, has the lowest water absorption, and is most resistant to freeze-thaw cycles. And unlike many synthetic slates, Celadon Ceramic Slate will not produce unsightly white salt deposits and will not chip, flake off or fade over time, as natural slate is prone to do.

Roof tiles are made from similar clay to bricks, such as Etruria marl, but for both hand and machine made roof tiles, the raw materials have to be screened to a finer grade than for brick manufacture. Traditional red, brown, buff, brindled or ‘antique’ ceramic roof tiles are unglazed with a plain or sanded finish. Where bright colours are required in roof tiles, high and low gloss pantiles are available in a range of strong colours, or to individual specification.

For plain roof tiles, a range of standard roof tile fittings is available for hips, valleys, eaves, ridges, verges, and internal and external angles. Clay tiles are one of the most decorative of historic roofing materials because of their great variety of shapes, colors, patterns, and textures. Their unique appearance makes them a prominent feature on an older house - helping define its architectural character.

In Japan, Kawara is the word the Japanese use to describe roof tiles in general, though there are in fact many styles and types of tiles with regional variations, and a large and specialized vocabulary is used to describe these. Japanese roof tiles are typically very well made and often outlive their intended function protecting structures from the elements. As a result, old roof tiles can sometimes be spotted in Japan being reused for unique and interesting purposes. Old roof tiles are sometimes used to reinforce earthen retaining walls, or stacked one next to another to make garden borders. Roof tiles are also buried vertically along dirt walkways with just the tips exposed a fraction of an inch above the surface to create artistic patterns and to act as paving surfaces.