Metal corsets (also known as iron corsets) are a type of historical corset or bodice made entirely out of metal, usually iron or steel. The metal corset was popularly claimed to have been introduced to France by Catherine de' Medici in the 16th century, although this is now considered a myth. The idea that such garments were worn for fashionable purposes is debatable, with fashion historians now regarding such claims sceptically. Many of the original metal bodices that have survived are now believed to have been intended for medical purposes as orthopaedic support garments and back braces. Such garments were described by the French army surgeon Ambroise Paré in the 16th century as a remedy for the "crookednesse of the Bodie."

Some of the more extreme examples of metal corsets that have survived are now generally thought to be later reproductions designed to appeal to fetishists, rather than garments intended for fashionable wear.

Metal medical corsets were still being made in the 20th century, whilst, since the late 20th century, fashion designers such as Alexander McQueen and Issey Miyake have made contemporary metal bodices and corsets from wire and aluminium coils.

Early fashion historians and writers have often attributed the introduction of fashionable corset-wearing to Catherine de' Medici, who is said to have brought metal corsets to France from Italy in the 16th century. The fashion historian Valerie Steele noted that after 19th-century writers catering to audiences for tightlacing and sexual fetishism played up the sadomasochistic idea of a "cruel, tortuous fashion" enforced by a dominant queen who demanded unrealistically small waists from her subjects, this mythical royal connection captured public imagination and became part of fashion mythology.

It is now widely believed that authentic metal corsets were intended as a form of orthopaedic brace to address spinal issues such as scoliosis. The 16th-century French army surgeon Ambroise Paré described metal corsets as intended "to amend the crookednesse of the Bodie," recommending that the iron should be perforated in order to make the garments lighter, and that they be made to fit and padded for comfort. Paré criticised the concept of corsetry as a waist-training device, warning that such a practice risked deforming the figure.

A steel corset in the Stibbert Museum, Florence, Italy, is dated to the mid-16th century, and thought to be similar to the metal stays recorded as having been made by a corazzaio mastro (master armour-maker) for Eleanor of Toledo, and delivered to her on 28 February 1549. However, as Eleanor's wardrobe records do not list any boned or stiffened corsets, it is thought that her steel bodice was designed for medical or therapeutic reasons rather than worn as a fashionable garment.

Although surviving metal bodices are usually dated to the late 16th and early 17th century, Steele has stated that some of the more extreme and elaborate examples are fakes created from the 19th century onwards to cater to fetishistic "fantasies about women imprisoned in metal corsets". For example, Herbert Norris claimed in Tudor Costume and Fashion (1938) that a misbehaving wife would be locked into a metal corset by her husband until she promised to behave. One such iron corset, with a 14 in (360 mm) waist, was acquired by the Fashion Institute of Technology Museum and described as dating from 1580–1600, but is now considered to be a forgery from the turn of the 19th and 20th centuries. Steele noted suspicious similarities between this corset and an illustration first published in 1868 in The Corset and the Crinoline, a "fetishistic" book claiming to offer a historical overview of fashion, and draws parallels between such corsets and fake medieval chastity belts. Harold Koda, the former curator of the Metropolitan Museum of Art's Costume Institute, states that the excessive, mechanically produced regularity of the garment's structure is evidence for its being a 19th-century fabrication. Koda's take on the significant percentage of extant 19th-century metal corsets made in emulation of purported 16th-century models is that they were created to cater to a specialist market, perhaps for inclusion in collector's cabinets.

The fashion historians Cecil Willett Cunnington and his wife Phillis, both medical doctors, also stated firmly that surviving "iron bodies". when not medical garments, were usually "fanciful 'reproductions'", with no proof of their having genuinely been worn. Despite the explicit scepticism of fashion historians such as Steele and the Cunningtons, scholars outside the field of dress history sometimes treat these corsets as legitimate fashion garments. The anthropologist Marianne Thesander concluded that because such bodices fit the fashionable silhouette of their alleged period, they were probably authentic, and served the same purpose as other corsets.