This study aims to address students' low mathematical problem-solving skills and self-regulated learning by developing website-based mathematics learning media using the problem-based learning model. Learning that integrates website-based media allows for more independent learning activities in solving mathematical problems. This study uses the ADDIE model to test the validity, practicality, and effectiveness of the product. Website-based media met the validity criteria based on expert assessments with an average score of 137 from subject matter experts and 78.5 from media experts, and the research instruments were declared valid with an Aiken index ranging from 0.9 to 0.99. Website-based media meet the criteria for practicality based on an average teacher assessment of 90.5, an average student assessment of 50.1, and a learning implementation rate of 93%. Website-based media are proven to be effective through four indicators: (1) students who pass exceed the threshold of 80%. (2) One sample t-test results p-value <.05 and t-value >1.69, so that H_0 is rejected. This proves that website-based mathematics learning media are effective in improving students' mathematical problem-solving skills and self-regulated learning. (3) The results of the paired sample t-test show p-value <.05 and t-value >1.69, so that H_0 is rejected. This proves that there is a significant improvement in students' mathematical problem-solving and self-regulated learning abilities after using website-based mathematical learning media. This study is able to facilitate students' problem-solving and self-regulated learning abilities simultaneously in mathematics education.