  We present optical, near-infrared, and X-ray observations of the optical
afterglow (OA) of the X-ray rich, long-duration gamma-ray burst GRB 011211.
Hubble Space Telescope (HST) data obtained 14, 26, 32, and 59 days after the
burst, show the host galaxy to have a morphology that is fairly typical of blue
galaxies at high redshift. We measure its magnitude to be R = 24.95 +/- 0.11.
We detect a break in the OA R-band light curve which is naturally accounted for
by a collimated outflow geometry. By fitting a broken power-law to the data we
find a best fit with a break 1.56 +/- 0.02 days after the burst, a pre-break
slope of alpha_1 = -0.95 +/- 0.02, and a post-break slope of alpha_2 = -2.11
+/- 0.07. The UV-optical spectral energy distribution (SED) around 14 hours
after the burst is best fit with a power-law with index beta = -0.56 +/- 0.19
reddened by an SMC-like extinction law with a modest A_V = 0.08 +/- 0.08 mag.
By comparison, from the XMM-Newton X-ray data at around the same time, we find
a decay index of alpha_X = -1.62 +/- 0.36 and a spectral index of beta_X =
-1.21 +0.10/-0.15. Interpolating between the UV-optical and X-ray implies that
the cooling frequency is located close to ~10^16 Hz in the observer frame at
the time of the observations. We argue, using the various temporal and spectral
indices above, that the most likely afterglow model is that of a jet expanding
into an external environment that has a constant mean density rather than a
wind-fed density structure. We estimate the electron energy index for this
burst to be p ~ 2.3.
