  We investigate the discovery potential for long-lived particles produced in
association with a top-antitop quark pair at the (High-Luminosity) LHC.
Compared to inclusive searches for a displaced vertex, top-associated signals
offer new trigger options and an extra handle to suppress background. We design
a search strategy for a displaced di-muon vertex in the tracking detectors, in
association with a reconstructed top-antitop pair. For axion-like particles
with masses above the di-muon threshold, we find that the (High-Luminosity) LHC
can probe effective top-quark couplings as small as $|c_{tt}|/f_a =
0.03(0.002)/$TeV and proper decay lengths as long as $20(300)$ m, assuming a
cross section of $1$ fb, with data corresponding to an integrated luminosity of
150 fb$^{-1}$ (3 ab$^{-1}$). Our predictions suggest that searches for
top-associated displaced di-muons will explore new terrain in the current
sensitivity gap between searches for prompt di-muons and missing energy.
