BACKGROUND: Global policy recommendations suggest a task-shifted model of post-diagnostic dementia care, moving towards primary and community-based care. It is unclear how this may best be delivered. AIM: To assess the effectiveness and cost-effectiveness of primary care-based models of post-diagnostic dementia care. DESIGN AND SETTING: A systematic review of trials and economic evaluations of post-diagnostic dementia care interventions where primary care was substantially involved in care plan decision making. METHOD: Searches were undertaken of MEDLINE, PsychINFO, EMBASE, Web of Science, and CINAHL (from inception to March 2019). Two authors independently critically appraised studies and inductively classified interventions into types of care models. Random effects meta-analysis or narrative synthesis was conducted for each model where appropriate. RESULTS: From 4506 unique references and 357 full texts, 23 papers were included from 10 trials of nine interventions, delivered in four countries. Four types of care models were identified. Primary care provider (PCP)-led care (n = 1) led to better caregiver mental health and reduced hospital and memory clinic costs compared with memory clinics. PCP-led care with specialist consulting support (n = 2) did not have additional effects on clinical outcomes or costs over usual primary care. PCP-case management partnership models (n = 6) offered the most promise, with impact on neuropsychiatric symptoms, caregiver burden, distress and mastery, and healthcare costs. Integrated primary care memory clinics (n = 1) had limited evidence for improved quality of life and cost-effectiveness compared with memory clinics. CONCLUSION: Partnership models may impact on some clinical outcomes and healthcare costs. More rigorous evaluation of promising primary care-led care models is needed