Onion skin paper is a type of very light weight, almost translucent paper which somewhat resembles the outer skins of an onion. It is also relatively durable, given how lightweight it is, because it usually contains a high percentage of cotton fibers, which make for stronger paper. There are numerous practical applications for onion skin paper including airmail stationary, Bibles, and other situations where lightweight, strong paper is needed. Along with other specialty papers, onion skin paper is available from paper supply stores and companies in varying sizes to meet differing needs.

The weight of onion skin paper is very light; a stack of 500 sheets of bond size onion skin paper weighs around nine pounds (four kilograms) depending on the manufacturer. Bond size is 17 inches by 22 inches (43 by 56 centimeters), meaning that it can be readily cut in half into a standard letter sized sheet. The light weight of onion skin paper makes it ideal for situations where large amounts of records are being generated, but still need to be kept manageable. For this reason, onion skin paper is also often used to make duplicates, carbon copies, and records of official correspondence. While the official version may be sent out on regular paper, the records are kept compact on onion skin paper.

The finish of onion skin paper is usually cockled, meaning that it was air dried while it was being made. Cockled paper has a slightly wavy, hand made feel to it, along with a mildly dimpled finish. This property means that onion skin paper often crackles while it is being handled, as the sheets do not lie flat against each other. It also prevents leaves of onion skin paper from sticking to each other or other surfaces, a common problem with very light weight papers.

While onion skin paper and tracing paper are technically not the same thing, onion skin paper can be used for art tracing. It can also be used as an interleaving material in books with color plates which have the potential to be damaged. Entire books are also printed on onion skin paper when they have a lot of material which would otherwise make them very unwieldy. When handling a large onion skin text, such as some versions of the Bible or the Oxford English Dictionary, be aware that the larger pages are more subject to ripping if roughly handled than some other papers, so do not be hasty, even when an etymological argument is vital!