  A lepton collider in the multi-TeV range has the potential to measure the
trilinear Higgs self-coupling constant $\lambda_{hhh}$ via the W-fusion mode
$\ell^+\ell^- \rightarrow \nu_\ell \bar{\nu}_\ell h h$. In this paper we do a
generator-level study to explore how center-of-mass energy spread, cone size,
tracking resolution, and collision energy range affect how precisely a muon
collider can measure $\lambda_{hhh}$ in comparison to an $e^+e^-$ collider. The
smaller spread in center-of-mass energy and higher energy range of a muon
collider improve cross section while the larger cone required to reduce
beam-induced background hinders detection of double-Higgs events. Our results
motivate a more detailed study of a multi-TeV muon collider and innovative
detector and analysis technologies required for background rejection and
precision measurement.
