In spite of being rare, actinide elements provide the building blocks for many fascinating condensed-matter systems, both from an experimental and theoretical perspective. Experimental observations of actinide materials are difficult because of rarity, toxicity, radioactivity, and even safety and security. Theory, on the other hand, has its own challenges. Complex crystal and electronic structures are often encountered in actinide materials, as well as pronounced electron correlation effects. Consequently, theoretical modeling of actinide materials and their 5f electronic states is very difficult. Here, we review recent theoretical efforts to describe and sometimes predict the behavior of actinide materials and complexes, such as phase stability including density functional theory (DFT), DFT in conjunction with an additional Coulomb repulsion U (DFT+U), and DFT in combination with dynamical mean-field theory (DFT+DMFT).