  We present a unified model of infrared (IR), optical, ultraviolet (UV), and
X-ray light curves for the 1983 outburst of GQ Muscae (Nova Muscae 1983) and
estimate its white dwarf (WD) mass. Based on an optically thick wind model of
nova outbursts, we model the optical and IR light curves with free-free
emission, and the UV 1455 \AA and supersoft X-ray light curves with blackbody
emission. The best fit model that reproduces simultaneously the IR, optical, UV
1455 \AA, and supersoft X-ray observations is a 0.7 \pm 0.05 M_\sun WD for an
assumed chemical composition of the envelope, X=0.35-0.55, X_{CNO} =0.2-0.35,
and Z = 0.02, by mass weight. The mass lost by the wind is estimated to be
\Delta M_{wind} \sim 2 \times 10^{-5} M_\sun. We provide a new determination of
the reddening, E(B-V) = 0.55 \pm 0.05, and of the distance, \sim 5 kpc.
Finally, we discuss the strong UV flash that took place on JD 2,445,499 (151
days after the outburst).
