Reverse microemulsions have been used to control the nucleation and growth of magnesium aluminium layered double hydroxides (LDH). The reactants were prepared in aqueous solution and then dispersed in an isooctane–sodium dodecyl sulfate (DDS) microemulsion. Under these conditions magnesium aluminium LDH phases were obtained containing DDS as the charge-balancing interlayer anion. By adjusting the water : surfactant molar ratio (w = [H2O]/[Surf.]) of the microemulsion we were able to control the nucleation and growth of the LDH phases. In some cases LDH nanoplatelets exhibiting a uniform 14 Å monolayer thickness could be isolated and characterized by AFM.