Since 1984, a series of regional conferences on mathematical physics has been organized by physicists from Iran, Pakistan and Turkey to promote the research in mathematical and theoretical physics in the region. This volume, which derives from the XI Regional Conference on Mathematical Physics, comprises 8 review and 44 research articles on the most significant topics in mathematical and theoretical physics such as astrophysics and cosmology, conformal field theory, high energy physics, general relativity and plasma physics. The review articles are comprehensive and self-contained and report on the most important developments in the corresponding subjects. Each review article provides a complete list of references, which is especially useful for graduate students who are just starting their research activities; even ambitious undergraduates in physics can use these review papers as useful background material to go further into the subject and explore the research literature. They are contributed by prominent senior scientists: M Moniez (Laboratoire de l'Accelerateur Lineare, France) and V Sahni (Inter-University Centre for Astronomy and Astrophysics (IUCAA), India) in Astrophysics and Cosmology, W Nahm (Dublin Institute for Advanced Studies (DIAS), Ireland) in Conformal Field Theory, J Lukierski (University of Wroclaw, Poland) in Mathematical Physics, Riazuddin and Fayyazuddin (Quaid-i-Azam University, Pakistan) in High Energy Physics, N Dadhich (Inter-University Centre for Astronomy and Astrophysics (IUCAA), India) and A Qadir (National University of Science and Technology, Pakistan) in General Relativity, and N Tsintsadze (Tbilisi State University, Georgia) in Plasma Physics.