Natural convection of micropolar fluid in a right-angled wavy triangular cavity has been analyzed numerically. Governing equations formulated in dimensionless stream function, vorticity and temperature using the Boussinesq and Eringen approaches with appropriate initial and boundary conditions have been solved by finite difference method of the second-order accuracy. The effects of the dimensionless time, Prandtl number, vortex viscosity parameter, and undulation number on streamlines, isotherms, vorticity isolines as well as average Nusselt number at wavy wall and fluid flow rate inside the cavity have been studied. Obtained results have revealed essential heat transfer reduction and fluid flow attenuation with vortex viscosity parameter. (C) 2016 Elsevier Ltd. All rights reserved.