Selvage denim (also called selvedge denim) is a type of denim which forms a clean natural edge that does not unravel. It is commonly presented in the unwashed or raw state. Typically, the selvage edges will be located along the outseam of the pants, making it visible when cuffs are worn. Although selvage denim is not completely synonymous with unwashed denim, the presence of selvage typically implies that the denim used is a higher quality.

The word "selvage" comes from the phrase "self-edge", the natural edge of a roll of fabric. In this case, denim made on old-style shuttle looms. These looms weave fabric with one continuous cross thread (the weft) that is passed back and forth all the way down the length of the bolt. As the weft loops back into the edge of the denim it creates this “self-edge” or Selvage. Selvage is desirable because the edge can’t fray like lower grade denims that have separate wefts which leave an open edge that must be stitched. Shuttle looming is a more time-consuming weaving process that produces denim of a tighter weave resulting in a heavier weight fabric that lasts.

Shuttle looms weave a more narrow piece of fabric, and thus a longer piece of fabric is required to make a pair of jeans (approximately 3 yards). To maximize yield, traditional jean makers use the fabric all the way to the selvage edge. When the cuff is turned up the two selvage edges, where the denim is sewn together, can be seen. The selvage edge is usually stiched with colored thread: green, white, brown, yellow, and red (red is the most common). Fabric mills used these colors to differentiate between fabrics.

Most selvage jeans today are dyed with synthetic indigo, but natural indigo dye is available in smaller niche denim labels. Loop dying machines feed a rope of cotton yarn through vats of indigo dye and then back out. The dye is allowed to oxidize before the next dip. Multiple dips create a deep dark indigo blue.

In response to increased demand for jeans in the 1950's, American denim manufacturers replaced the old shuttle style looms with modern projectile looms. The new looms produced fabric faster and wider (60-inches or wider), yet lighter and less durable. Synthetic dyeing techniques along with post-dye treatments were introduced to control shrink and twist.