The outskirts of galaxies are a very good laboratory for testing the nature of the gravitational field at low accelerations .
By assuming that the neutral hydrogen gas is in hydrostatic equilibrium in the gravitational potential of the host galaxy , the observed flaring of the gas layer can be used to test modified gravities .
For the first time we construct a simple framework to derive the scaleheight of the neutral hydrogen gas disc in the MOND scenario and apply this to the Milky Way .
It is shown that using a constant gas velocity dispersion of \sim 9 km s ^ { -1 } , MOND is able to give a very good fit to the observed H i flaring beyond a galactocentric distance of 17 kpc up to the last measured point ( \sim 40 kpc ) .
Between 10 and 16 kpc , however , the observed scaleheight is about 40 \% more than what MOND predicts for the standard interpolating function and 70 \% for the form suggested by Famaey & Binney .
Given the uncertainties in the non-thermal pressure support by cosmic rays and magnetic fields , MOND seems to be a plausible alternative to dark matter in explaining the Milky Way flaring .
Studying the flaring of extended H i discs in external edge-on galaxies may be a promising approach to assess the viability of MOND .