We present the combination of measurements of the effective-leptonic weak mixing angle parameter $\sin^2 \theta^{\rm lept}_{\rm eff}$ from the CDF and D0 experiments using the full Tevatron data sets, corresponding to 9-10 fb$^{-1}$ of $p\bar{p}$ collisions. The inference of the standard model weak mixing angle parameter $\sin^2 \theta_W$ and equivalent indirect measurement of $M_W$ based on ZFITTER calculations is also made, yielding the combination results
$$\begin{eqnarray*} \sin^2 \theta^{\rm lept}_{\rm eff} & = & 0.23148 \pm 0.00033, \\ \sin^2 \theta_W & = & 0.22324 \pm 0.00033, \text{ and} \\ M_W & = & 80.367 \pm 0.017 \;{\rm GeV}/c^2. \end{eqnarray*}$$
These Tevatron measurements are consistent with the world-best measurements from electron-positron colliders. The uncertainties include statistical and systematic contributions and represent the best precision from hadron colliders, which nearly matches that of the best electron-positron individual measurements.