<p>There are many applications of mathematical physics in several fields of basic science and engineering. Thus we have tried to provide the Special Issue Modern Problems of Mathematical Physics and Their Applications to cover the new advances of mathematical physics and its applications. In this Special Issue we have focused on some important and challenging topics such as integral equations ill-posed problems ordinary differential equations partial differential equations system of equations fractional problems linear and nonlinear problems fuzzy problems numerical methods analytical methods semi-analytical methods convergence analysis error analysis and mathematical models. In response to our invitation we received 31 papers from more than 17 countries (Russia Uzbekistan China USA Kuwait Bosnia and Herzegovina Thailand Pakistan Turkey Nigeria Jordan Romania India Iran Argentina Israel Canada etc.) of which 19 were published and 12 rejected.</p>