Introduction Statistical shape analysis is one of the fields of multivariate statistics, where the main focus is on the geometric structures of objects. This analysis method is widely used in many scientific fields, such as medicine and morphology. One of the tools for diagnosing diseases or determining animal species is the images and the shapes extracted from them. Introducing methods of classifying shapes can be a solution to determine the class of each observation. Usually, in regression modelling, explanatory and dependent variables are quantitative. However, one may want to measure the relationship between an explanatory variable (with continuous values) and a dependent variable with qualitative values. One option is to use the Multinomial logistic regression model. Therefore, a semiparametric Multinomial logistic regression model to classify shape data is introduced in this paper. Material and Methods The power-divergence criterion is a measure for hypothesis testing in Multinomial data. This criterion is used to define the kernel function of explanatory variables. The model is a Multinomial logistic regression model based on kernel function as a function of explanatory variables and an intercept. Since the shapes’,geometric structure and size play a key role in the classification of shapes, the kernel function is determined based on the shape distances. The smoothing parameter was estimated using the least square cross-validation method. Also, the estimation of model parameters was done using the neural network method. Results and Discussion The shape space is a manifold, but most of the methods presented in the literature for classifying shapes were done in the shape tangent space or used linear transformations. Since mapping from the manifold to linear space decreases data information, applying tangent space and linear spaces will reduce classification accuracy. Therefore, the shape space is used to classify the shape data. The performance of the model in a simulation study and two real data sets were investigated in the paper. The two real data sets used in this paper are taken from the shape package in R software. The first data set is related to schizophrenia patients and people as control, and the second one is associated with the skull of three species of apes of two sexes. The classification of these data showed an accuracy of 82% and 84%, respectively. Also, a comparison was made with the previous methods based on a real data set, which showed the proper performance of our approach compared to the other two techniques. Conclusion Since in the nonparametric kernel function, suitable distances of the shape space were used, the introduced method performs better than those based on Euclidean spaces. Also, the ability to use other shape distances, such as partial, full Procrustes and Riemannian distances, makes the model more flexible in classifying different types of shape data. On the other hand, sizeand-shape distance can be used in the kernel function to classify data whose size plays a key role in their geometric structure. Furthermore, since few statistical Distributions have been introduced in the shape space, nonparametric methods can be helpful in the analysis of shape data. However, using nonparametric methods in the shape space is time-consuming from the point of view of computer calculations.