This study explored trends in problem solving in mathematics research from 2000 to 2020. A total of hundred (100) articles related to mathematical problem solving were examined from the selected journal articles available online. Topical issues as well as methodological trends (research methods, type and size of sample, tools for data collection and techniques for data analysis) were investigated. Content analysis was employed to analyse the sampled data using open codes according to the categories, and themes were generated for some research questions. The results showed that topical issues mainly investigated in mathematical problem solving within the trend period were problem solving ability, teaching, meta-cognition, thinking through, views, process, strategies, creativity, difficulties, efficacy, assessment, performance, representation, and problem-solving curriculum respectively. Methodological trends showed a preference for the qualitative research method. Tests and interviews were the dominant data collection tools utilized while qualitative descriptive analysis was the most preferred data analysis technique. It is therefore concluded that this study can serve as a foundation for further studies and an enhanced study on mathematical problem solving.