The potency of three chemical compounds as resistance inducer in tomato plants against root-knot nematode (Meloidogyne incognita) were evaluated using split root system technique. Salicylic acid (SA), Ascorbic acid (AS) and Dipotassium hydrogen phosphate (DKP) was assessed at three concentrations (10, 20 and 50 mM) and the activity of cytoplasmic peroxidase and Phenol oxidase in tomato leaves were measured. Results indicated that application of these inducers significantly reduced all nematode related parameters in tomato plants under greenhouse conditions. Salicylic acid (SA) at 50 mM demonstrated the highest reduction in number of second stage juveniles in 250 mg soil, number of galls, egg masses and females/tomato root system compared to inoculated untreated control. These treatments significantly enhanced plant growth parameters of tomato plants i.e., plant height, root length, fresh root, shoot weight and dry shoot weight. Moreover, these resistance inducers enhanced the synthesis and activity of defence enzymes in tomato plants. Phenol oxidase and peroxidase drastically increased in the treated plants compared with un-treated control plants. Application of SA, AS and DKP may provide an environmentally friendly management strategy against root-knot nematode infection in tomato through induction of systemic resistance.