We present the studies of the third- and higher-order nonlinear optical processes in barium titanate ( $\mathrm{Ba}\mathrm{Ti}{\mathrm{O}}_3$ ) and strontium titanate ( $\mathrm{Sr}\mathrm{Ti}{\mathrm{O}}_3$ ) nanoparticles. We measured the nonlinear refractive indices and nonlinear absorption coefficients of the $\mathrm{Ba}\mathrm{Ti}{\mathrm{O}}_3$ and $\mathrm{Sr}\mathrm{Ti}{\mathrm{O}}_3$ nanoparticles dissolved in ethylene glycol using the $790\mathrm{nm}$ fs and ps pulses. The high-order harmonic generation up to the 39th order was achieved in the $\mathrm{Ba}\mathrm{Ti}{\mathrm{O}}_3$ and $\mathrm{Sr}\mathrm{Ti}{\mathrm{O}}_3$ nanoparticles-contained plumes when the femtosecond radiation propagated through the preformed plasma. The $1\times {10}^{-6}$ and $4\times {10}^{-6}$ high-order harmonic efficiencies at the plateau region were achieved in the cases of the $\mathrm{Ba}\mathrm{Ti}{\mathrm{O}}_3$ and $\mathrm{Sr}\mathrm{Ti}{\mathrm{O}}_3$ nanoparticles-contained plasmas.