The present study describes the stadial time and comparative morphometric variations of each post embryonic developmental stage of rice grasshopper, Oxya japonica. Measurements of body parts including total body length, antennal length, pronotum length, pronotum width, head length, prothoracic leg, mesothoracic leg, metathoracic leg, abdominal length, abdominal width and hind femur length of instar stages and adult male and female hoppers were made. Statistical analysis of the measurements revealed a progressive increase and significant differences in the morphology of various instars and adults. The study on the growth and development revealed that O. japonica is a highly fertile species and its fecundity is affected by various abiotic factors. The number of instars recorded in the present study was five. The stadial time of lower instars (first to third) was much lower than those of the higher instars (fourth and fifth) and adults owing to the rapid development of early instars. A strong relationship between the stages and the stadial time was observed in correlation analysis. The average pre-oviposition period, average oviposition period and average post-oviposition period was recorded to be 6.2±0.50, 18.14±0.07 and 4.98±0.31 days, respectively. The average longevity of male and female was 36.4±0.52 and 38.84±0.15 days, respectively. The information is pivotal for the understanding of O. japonica behaviour and for devising various control strategies against it.