Broomrape (Orobanche cernua Loefl) is an obligate, non-chlorophyllous, and root-parasitic plant that causes substantial yield losses in tomato production by establishing a direct connection with host roots. Its prolific seed production, prolonged seed persistence in soil, and the difficulty of effective control make its sustainable management a major challenge. This study evaluated the efficacy of two resistance-inducing compounds, isonicotinic acid (INA) and benzothiadiazole (BTH), applied at concentrations of 0, 100, and 500 mg/L, for the suppression of broomrape under field conditions. Tomato seedlings were treated with the respective solutions before transplanting into artificially infested soil, and the same compounds were subsequently applied through irrigation 15 days after transplanting. The results demonstrated that INA and BTH significantly suppressed broomrape development by reducing the number of tubercles, nodule attachments, emerged shoots, and the dry weight of broomrape aerial biomass. Both compounds also significantly improved tomato growth under broomrape infestation. Isonicotinic acid at 500 mg/L exhibited the greatest suppressive effect, completely inhibiting broomrape aerial biomass production, markedly reducing the number of nodule attachments, and delaying broomrape shoots emergence by approximately 25 days compared with BTH treatment. Moreover, INA-treated plants showed the greatest plant height, shoot and root dry weights, and the highest numbers of flowers and fruits. These findings indicate that induced resistance, particularly by applying INA at 500 mg/L, represents an effective and environmentally compatible approach that can be integrated into the sustainable management of O. cernua in tomato production under field conditions.