Dye-sublimation printing (or dye-sub printing) is a term that convers several distinct digital computer printing techniques that involve using heat to transfer dye onto a substrate.

The sublimation name was first applied because the dye was thought to make the transition between the solid and gas states without going through a liquid stage. This understanding of the process was later shown to be incorrect, as there is some liquefication of the dye. Since then, the proper name for the process has become known as dye diffusion, though this technically correct term has not supplanted the original name.

Historically, "dye sublimation" referred to page printers that use a thermal printhead to transfer dye from a ribbon directly onto the print media via sublimation. While it originally was used in creating prepress proofs, today this technology survives in ID card printers and dedicated photo printers, often under the name dye diffusion thermal transfer (D2T2).

The term was later also applied to the indirect sublimation transfer printing process, which uses a standard printer to deposit sublimation-capable toner or ink onto a transfer sheet. The printed transfer sheet is then pressed with the substrate with heat, transferring the dye to the substrate, such as plastic or fabric, via sublimation. Thus, this process is indirect, since the final substrate does not pass through the printer, and the sublimation step occurs separately.

The term direct dye sublimation is sometimes applied to a variant of digital textile printing using dye-sublimation inks printed directly onto fabric, which must then be heated to set the dyes, without the use of a transfer sheet.