Entropy of solid, liquid, and gas at triple point of water
Triple point defines a situation of simultaneous equilibrium between the solid, the liquid and the gas phases.

For such an equilibrium, you simply write:

$$
\Delta S= \frac{\Delta H}{T}
$$

that rises from the fact that $\Delta G=0$. 

Considering water molar ($m$) enthalpies for each phase transition at $273\,K$:

$$
\Delta H_{melting,m}=6.01\,kJ\,mol^{-1}
$$
$$
\Delta H_{vaporisation,m}=45.05\,kJ\,mol^{-1}
$$
$$
\Delta H_{sublimation,m}=51.06\,kJ\,mol^{-1}
$$

one realises that 


the entropy of the gas phase is higher than the entropy of the liquid phase.
the entropy of the liquid phase is higher than the entropy of the solid phase


In this respect the triple point has no peculiar behaviour compared to other points where a two-phase equilibrium is established.