Recent advances in the development of low-dimensional materials such as two-dimensional transition-metal dichalcogenides (2D TMDCs) and metal halide perovskites have attracted a lot of attention. These low-dimensional materials have been shown properties suited for photonics and optoelectronics applications, opening up new possibilities for micro/nano lasing applications. In this article, we review 2D TMDCs and perovskites as gain mediums in micro/nano lasers. First, we give a brief introduction about the principles of lasing. Second, the micro/nano lasers by using 2D TMDCs as gain medium are discussed. Third, the micro/nano lasers by using perovskites as gain medium are summarized. The lasing characteristics such as cavity types, emission wavelengths, coherence properties and lasing thresholds are compared and discussed to show the pros and cons of these two kinds of materials. The future perspectives for the development of micro/nano lasers based on these two materials are discussed.