Graph paper is paper that is printed with fine lines making up a grid. It is typically used for drawing diagrams, with the lines being used as guides for the drawing. It is commonly found in engineering settings for quick drawings and sketches. It can also be used for plotting mathematical functions manually. Some specialized forms of graph paper have logarithmic scales or allow plotting in polar coordinates. Quad paper is a common form of graph paper in imperial unit countries where the grid is a quarter inch apart printed in light blue and right to the edge of the paper.

3D graph paper is also available, but fairly rare. It uses a series of three guidelines forming a 60-degree grid, so that the paper is covered with small triangles. It is used for drawing isometric views.

Graph paper is typically sold in pads of 100 sheets with a cardboard backing to draw on. It is also sold in hardcover books for use as engineering notebooks.

Computer plotting programs have supplanted many of the former uses of graph paper, much as calculators have supplanted slide rules.