A nib is the part of a quill, dip pen, fountain pen, ball point, or stylus which comes into contact with the writing surface in order to deposit ink. Different types of nibs vary in their purpose, shape and size, as well as the material from which they are made.

The quill replaced the reed pen across Europe by the Early Middle Ages and remained the main writing tool of the West for nearly a thousand years until the 17th century. Quills are fashioned by cutting a nib into the end of a feather obtained from a fairly large bird, such as a goose, traditionally from its left wing. A quill has the advantage of being more durable and more flexible than a reed pen, and it can also retain ink in the hollow shaft of the feather, known as the calamus, allowing more writing time between ink dippings. The quill was in common use until the early 19th century and the advent of the metal nib. For business purposes, the quill was fairly quickly overtaken; however, it remains popular for personal use and for artistic work.

Metal nibs have their origins as far back as ancient Egypt and were made of metals like copper and bronze. However, the quality of writing that could be achieved with these pens was inferior to that of reed pens. Metallic nibs were made up through the 18th-century as one-off, craftsman-made luxury items. In the early 1800s, Wise in Britain, and Peregrine Williamson in the United States were the first recorded makers of steel pens as their primary occupation. It was not until the 1820s, when John Mitchell, Josiah Mason and others set up a factory in Birmingham, England to manufacture steel nibs, that their popularity took off. The metal nib retains a sharp point or edge much longer than the quill, which wears out more quickly and requires much skill to sharpen. Metal nibs are also easily manufactured to have different properties for different purposes. Also, they can now be attached to and removed from holders, allowing one to switch between nibs with relative ease.

Pen nibs come in a variety of different shapes and sizes for different purposes but can be split into two main types: broad nibs and pointed nibs.

The broad nib, also called broad-edge or chisel-edge, is the older of the two nib types. It is rigid and has a flat edge. The pen is usually held at a constant angle to the horizontal; different scripts require different nib angles. Thick and thin strokes are created by varying the direction of the stroke.

Many writing styles have developed over the centuries with the broad nib, including the medieval Uncial, Blackletter and Carolingian minuscule scripts (and their variants), the Italic Hand of the Renaissance, and more recently Edward Johnston's Foundational Hand, developed in the early 20th century.

The pointed nib is flexible and comes to a sharp point rather than a broad edge. Thick and thin strokes are achieved by varying the amount of pressure on the nib. Thick lines are created on downstrokes by pushing down on the nib, causing the nib tines to splay and allowing more ink to flow through the widened slit onto the writing surface. Lighter pressure produces less flexing of the tines, creating thinner strokes. The finest hairline strokes are created on the upstrokes and sideways strokes. Due to the shape of the pointed nib, thick lines can only be produced on downstrokes. If too much pressure is applied to the pen on an upstroke, the nib tines are likely to dig into the paper.

Pointed nibs originated in the 17th century and were initially created by hand from quills in a similar fashion to broad-edge nibs. Towards the end of the Industrial Revolution in the early 19th century, high demand for nibs coupled with steel manufacturing processes eventually led to the mass production of the steel nib. Pointed nibs also led to the development of newer styles of penmanship such as the English Round Hand and Copperplate scripts during the 17th and 18th centuries, as well as the Spencerian script in the 19th century.