The Esterbrook Pen Company is a former American manufacturing company founded by English immigrant Richard Esterbrook and based in Camden, New Jersey. It was the largest pen manufacturer in the United States, having reached a record of producing 216,000,000 pens a year. The company produced dip pens, then concentrating on fountain pens until it was acquired by Venus Pencils in 1967, ceasing activities in 1971.

A dip pen is a writing instrument used to apply ink to paper. It usually consists of a metal nib with capillary channels like those of fountain pen nibs, mounted in a handle or holder, often made of wood. Other materials can be used for the holder, including bone, metal and plastic; some pens are made entirely of glass.