The present study was initiated to explore at the nematicidal activity of some nanoemulsions of monoterpenes, i.e. (R)-carvone, cinnamaldehyde, citral, geraniol and pulegone against tomato knot-root nematode M.  javanica, in both laboratory and under greenhouse conditions The results show that the pure and NE-monoterpenes tested considerably and severely decreased egg hatching at doses ranging from 25 to 1000 μg/ml. NE-Cinnamaldehyde, significantly, showed higher J2 mortality  (90.67 %) and egg-hatching inhibition (8.67) than pure cinnamaldehyde. The most successful therapy for reducing root galls and the number of egg masses was NE- Cinnamaldehyde, which showed 90.3% and 92.8% reduction, followed by NE- Pulegone 84.2% reduction, respectively. The population of J2 in soil was considerably decreased after using the tested nanoemulsion monoterpenes. NE- Cinnamaldehyde was the most effective treatment, suppressing the final population of M. javanica by 81.8%. Beyond oxamyl, NE-Cinnamaldehyde was the most efficient treatment for increasing the weights and lengths of both fresh shoots and roots in infected tomato plants, consecutively. Meanwhile, pulegone measured the intermediate values of fresh root and shoot weights as well as for lengths. Normal and nanoemulsion cinnamaldehyde ranked the first as it increased polyphenoloxidase (PPO) activity, compared to the other treatments followed by nanoemulsion and normal pulegone. The highest enzyme activity was noticed 7 and 15 days after treatment. Peroxidase activity (POD) also increased by nanoterpene treatments in a trend similar to that of the PPO. Consequently, these effective monoterpene nanoemulsions could be effective potentially and environmentally safe to control tomato knot-root nematode.