The present investigation was carried out to evaluate the ontogenic allometry in Diogenes alias McLaughlin & Holthuis, 2001 using multivariate allometric coefficient. The hermit crab specimens were collected bi-weekly from trawl fishing grounds for one year period. A set of four morphometric variables were extracted from each collected specimens: left chela length and width and cephalothoracic shield length and width. Jolicoeur's multivariate allometric coefficient was used to estimate the allometry between sexes. From the study, it is noted that negative allometry was observed for cheliped length, cheliped width presented isometric growth, shield length with positive allometry and shield width for females had isometric growth while the males had negative allometric growth. Although, sexual dimorphism was similar in both male and female, but it is more pronounced in males. As animal grows, sexual dimorphism also increases with size.