Disclosed is an adjustable holder for devices with a simplified design for accommodating devices of various form factors and shapes. The adjustable holder comprises at least a pair of offset, generally parallel arms that are slidable within corresponding openings of a support in order to adjust the arms and fixedly position the arms at varying distances relative to the support. The adjustable holder further comprises a gripping member coupled to a distal end of each of the arms to grip a device at opposing sides of the device. In some embodiments, the arms are adjustable via a two-part ratcheting mechanism. In yet other embodiments, the gripping members are rotatable to accommodate devices of various geometries. The holder can fit onto a stand or structure to hold a device in a fixed position.