Boro (ぼろ) are a class of Japanese textiles that have been mended or patched together.

The term is derived from the Japanese term "boroboro", meaning something tattered or repaired. The term 'boro' typically refers to cotton, linen and hemp materials, mostly hand-woven by peasant farmers, that have been stitched or re-woven together to create an often many-layered material used for warm, practical clothing.

Historically, it was more economical to grow, spin, dye, weave and make one's own clothing over buying new garments, and equally as economical to re-use old, worn-out clothing as fabric for new garments; warmer fibres, such as cotton, were also less commonly available, leading to the development of layering as a necessity in the creation of lower-class clothing.

Boro textiles are typically dyed with indigo dyestuff, historically having been the cheapest and easiest-to-grow dyestuff available to the lower classes. Many examples of boro feature kasuri dyework, and most extant examples of boro today are antiques or modern reproductions made as a craft project, with the introduction of cheaper ready-to-wear clothing to early 20th century Japan rendering the creation of boro mostly unnecessary.

During the Edo period, fine silk and cotton fabrics were reserved for a select portion of the upper classes, either through official edicts of dress, or the simple factor of cost; silk fabrics were also unsuitable for working clothes, leading to most practical clothing being developed with the aim of practical wear. Many working-class people grew, spun, dyed and wove their own clothing, leading to the development of other fabrics, such as kasuri.

Due to the economic nature of repairing, re-using and re-weaving old clothing and fabrics, boro also developed out of a working-class need for inexpensive textiles, predominantly coming to signify the clothing of the peasant farming classes over time. Garments and textiles were repaired with spare fabric scraps out of necessity, and in many cases, the usage of repaired clothing lasted for several generations, leading to garments eventually resembling a complex and many-layered patchwork spanning decades of mending.

The usage of indigo dyestuff (ai) and indigo dyeing techniques (aizome) was common, with indigo dyes often being the only dyestuff available to use by the peasant classes. Indigo dye would often be grown and processed by the peasant classes themselves, being generally easy to grow, and also added a layer of protection to garments due to its moth-repelling properties.

Dyeing fabrics with indigo was also incredibly economic, as one indigo dyebath could be used to dye fabric a number of times, in contrast to the average dyebath having just one use.