The Sigma 30mm f/1.4 EX DC HSM is a wide-aperture photographic lens made by the Sigma Corporation, equipped with a Hyper Sonic Motor (abbreviated HSM, Sigma's trade name for photo lens focusing technology using ultrasonic motor). The lens was produced in Canon EF mount, Four Thirds System, Nikon F-mount, Pentax K mount, the SA mount, and the Sony/Minolta AF Mount varieties, all of the same optical formula. It shipped with a removable petal-type lens hood (62mm diameter). The lens assumes a crop factor of roughly 1.5, and therefore is not usable with on full-frame or 135 film cameras.

In 2013, Sigma announced that the lens would be replaced by a redesigned model designated as the Sigma 30mm f/1.4 DC HSM A; the new lens went on sale in March of that year in Canon, Nikon, and Sigma mounts.

Its large aperture allows for a shallow depth of field, allowing good isolation of close subjects. On APS-C sensor cameras, its field of view equivalent to that of a 46mm lens (Nikon DX, Pentax, Sony, current Sigma bodies), 48mm lens (Canon), 51mm lens (older Sigma bodies) or 60mm lens (Four Thirds). On the Four-Thirds mount, it is the only affordable normal, large aperture lens, therefore it is popular lens on that format.