Field-responsive BaTiO₃ nanoparticle/organic hybrid-based fluids were synthesized from Ba–Ti double alkoxide under controlled hydrolysis conditions. Nanocrystalline BaTiO₃ particles chemically modified with polarizable ligands were synthesized through hydrolysis of modified metal–organics below 100°C. The modified BaTi alkoxide was hydrolyzed, yielding BaTiO₃ particles modified with organics. A heterogeneous fluid consisting of modified BaTiO₃ particles and silicone oil revealed a typical electrorheological (ER) behavior on application of a direct current (DC) field. The ER behavior was found to be dependent on the type of ligand. Among the 4-substitued benzyloxy ligands examined in the ER measurement, 4-fluorobenzyloxy modifier revealed the highest yield stress. A transparent BaTiO₃ particle/dimethylsiloxane hybrid fluid was prepared by adding carbinol-modified dimethylsiloxane to a solution of sol–gel-derived BaTiO₃ nanoparticles. The transmittance of the fluid showed a response to an external electric field. The curve of shear stress versus shear rate for the hybrid fluid was varied by applying both DC and alternating current (AC) fields. The behavior of the nanoparticle-based fluid was attributed to the interfacial polarization between the BaTiO₃ nanoparticles and the functional modifiers.