This paper analyses the bond behaviour of steel reinforcement bars in the matrix of nano-silica (NS)-modified self-consolidating engineered cementitious composites (SC-ECC). Presented first is the results of pull-out tests performed on three different diameters (12 mm, 16 mm, 20 mm) sizes of reinforcing steel bar embedded in the matrix. Subsequently, the results of the experiment are used in identifying the bond-slip relationship which explains the interactions between steel bars and matrix. A response surface methodology is applied to develop predictive models which are used to perform multi-objective optimization on bond-slip properties such as bond energy, bond slip and bond strength. Lastly, the experimental and predicted results obtained demonstrate that the developed models are suitable for the interpretation of the bond behaviour of steel bars embedded in the NS-modified cementitious matrix. © 2019 Elsevier Ltd