Mobility is essential to maintaining independence for older adults. This systematic review aimed to summarize evidence about self-reported risk factors for self-reported mobility decline; and to provide an overview of published prognostic models for self-reported mobility decline among community-dwelling older adults. Databases were searched from inception to June 2, 2020. Studies were screened by two independent reviewers who extracted data and assessed study quality. Sixty-one studies (45,187 participants) were included, providing information on 107 risk factors. High-quality evidence and moderate/large effect sizes for the association with mobility decline were found for older age beyond 75 years, the presence of widespread pain, and mobility modifications. Moderate-high quality evidence and small effect sizes were found for a further 21 factors. Three model development studies demonstrated acceptable model performance, limited by high risk of bias. These findings should be considered in intervention development, and in developing a prediction instrument for practical application.