Mechanical properties of simplified model of ferrite/cementite lamellar structure in pearlite steel wire are examined by a strain gradient crystal plasticity analysis. Bagaryatsky and Pitsch-Petch relationships are used to determine crystallographic orientations of ferrite and cementite phases. Obtained results show that yield stress and strain hardening rate increase with reduction of lamellar thickness of ferrite layer and this increase is larger in the model with Bagaryatsky relationship than that with Pitsch-Petch one. Detailed mechanism that leads to this significant change in macroscopic mechanical response is discussed from the view point of dislocations’ behavior. Strain incompatibility effect between phases on the mechanical response is shown to be relatively small.