Implant adapters and related methods are disclosed herein. Exemplary adapters can allow a single connector to be used interchangeably for rod-to-rod, rod-to-anchor, or anchor-to-anchor attachment. In some embodiments, the adapter can fit within tight spaces, can be adjustable in one or more degrees of freedom, or can be configured to “snap” onto a rod and/or to “drag” against the rod, e.g., for provisional retention and positioning of the connector prior to locking.