In this thesis a web application for seismic vulnerability analysis of masonry buildings, which was developed in PHP programming language, is presented. Firstly, masonry buildings and their behaviour during the seismic event are briefly described. Follows a description of the theoretical background of the simplified nondlinear analysis for seismic performance assessment of masonry buildings. The method is based on simplified pushover analysis with consideration of storydshear plastic mechanisms and the incremental dynamic analysis, which is performed by equivalent single degree of freedom model. Results of the analysis are simplified IDA curves. They can be used to estimate a sample of maximum acceleration causing different limit states, which represents the input data for the calculation of the structure’s seismic fragility curves. Different set of accelergorams, which were selected to be used in the web application, and the procedure for calculation of seismic fragility curves are also presented. In the fifth chapter, the procedure, principles and programming languages used to create the application are described. Follows description and demonstration of the use of web application. For the investigated masonry building it is shown that the limitdstate accelerations obtained by the web application are similar to the results based on the equivalent frame model. Some larger difference can be observed in the distribution of damage in structural elements for a designated limit state. In the conclusion, possibilities for future development and use of the application is discussed.