Background: The number of people worldwide with dementia is currently estimated at 50 million and is expected to rise almost three-fold by 2050. To decrease dementia-related behavioral symptoms and support the ability to function in their everyday lives, it is critical to develop practical, evidence‐based nonpharmacological interventions as no pharmacological treatments are available to cure dementia. We investigated existing nonpharmacological programs for people with dementia and explored factors related to the effectiveness of these types of programs. Methods: We performed a systematic search in the literature to identify nonpharmacological intervention programs developed for people with dementia and reviewed 36 randomized controlled trials. Among several outcomes reported in each study, we focused on the most common outcomes including quality of life, neuropsychiatric symptoms, depression, agitation, and cognition for further review. Results: Thirty-six articles were classified into 6 categories: psychosocial practices, training program for staff or caregiver, cognitive therapy, exercises, occupational therapy and sensory practices. Several factors were identified that might affect the outcomes of nonpharmacological interventions for people with dementia including study design, characteristics of the intervention, maintaining research participants, heterogeneity issues, and implementation fidelity. About half of studies in this review reported positive program effects on their targeted outcomes, such as WHELD-PCC on improving quality of life, neuropsychiatric symptoms and agitation; Cognitive Stimulation Therapy on quality of life, neuropsychiatric symptoms and cognition; and STA OP! on neuropsychiatric symptoms, depression and agitation. Conclusion: We found that some programs even with a rigorous study design did not produce expected outcomes. Other programs that reported positive outcomes with poor designs need to be reviewed and replicate to verify the outcomes. Factors such as individual tailored and customized interventions, promoting social interactions, easiness and compatibility of interventions, and developing program theory need to be considered when developing nonpharmacological intervention programs.