The random free energy barrier hopping model is used to investigate the temperature and frequency dependent ac conductivity $$\sigma _{ac}(\omega )$$ of binary chalcogenide glasses $${\text {Se}}_{100-x}{\text {X}}_{x}$$ (X = Ge, In, Te). The temperature dependent barrier height leads to Meyer–Neldel (MN) rule. The calculated MN energy $$E_{MN}$$ is in good agreement with the experimental estimates. The $$\sigma _{ac}(\omega )$$ is taken as the sum of bipolaron and single polaron hopping conductivities $$\sigma _{b}(\omega )$$ and $$\sigma _{s}(\omega ),$$ respectively. The calculated results are in close agreement with the experimental data. It is found that $$\sigma _{s}$$ is smaller by orders of magnitude than $$\sigma _{b}$$ in $${\text {Se}}_{100-x}{\text {Ge}}_{x}$$ alloys in the temperature range 250–400 K, while in $${\text {Se}}_{100-x}{\text {Te}}_{x}$$ alloys $$\sigma _{ac}(\omega )$$ is mainly due to $$\sigma _{b}$$ in the temperature range 150–250 K and $$\sigma _{s}$$ becomes significant above 250 K. However in $${\text {Se}}_{100-x}{\text {In}}_{x}$$ alloys in the temperature range 303–333 K, $$\sigma _{b}$$ is nearly temperature independent and $$\sigma _{ac}(\omega )$$ is mainly due to $$\sigma _{s}.$$ It is found that acoustic phonons assist hopping process in $${\text {Se}}_{100-x}{\text {Ge}}_{x}$$ and $${\text {Se}}_{100-x}{\text {Te}}_{x}$$ alloys, while both high energy acoustic and low energy optical phonons assist hopping process in $${\text {Se}}_{100-x}{\text {In}}_{x}$$ alloys.