  We study target space entanglement in gauged multi-matrix models as models of
entanglement between groups of D-branes separated by a planar entangling
surface, paying close attention to the implementation of gauge invariance. We
open with a review of target space entanglement between identical particles,
which shares some important features (specifically a gauged permutation
symmetry) with our main problem. For our matrix models, we implement a gauge
fixing well-adapted to the entangling surface. In this gauge, we map the matrix
model problem to that of entanglement of a $U(1)$ gauge theory on a complete or
all-to-all lattice. Matrix elements corresponding to open strings stretching
across the entangling surface in the target space lead to interesting
contributions to the entanglement entropy.
