3D joining of microelectronic components and a conductively self-adjusting anisotropic matrix are provided. In an implementation, an adhesive matrix automatically makes electrical connections between two surfaces that have electrical contacts, and bonds the two surfaces together. Conductive members in the adhesive matrix are aligned to automatically establish electrical connections between at least partially aligned contacts on each of the two surfaces while providing nonconductive adhesion between parts of the two surfaces lacking aligned contacts. An example method includes forming an adhesive matrix between two surfaces to be joined, including conductive members anisotropically aligned in an adhesive medium, then pressing the two surfaces together to automatically connect corresponding electrical contacts that are at least partially aligned on the two surfaces. The adhesive medium in the matrix secures the two surfaces together.