BACKGROUND: Despite widespread use, there are few studies evaluating the consumer Choosing Wisely questions. METHODS: We evaluated the impact of the Choosing Wisely questions on consumers' decision-making outcomes. Adults living in Australia were presented with a hypothetical low-value care scenario. Using a 2×2×2 between-subjects factorial design, they were randomized to either the Choosing Wisely questions ("Questions"), a shared decision-making (SDM) preparation video ("Video"), both interventions, or control (no intervention). Primary outcomes were 1) self-efficacy to ask questions and be involved in decision-making and 2) intention to engage in SDM. RESULTS: A total of 1,439 participants (45.6% with "inadequate" health literacy) were eligible and included in the analysis. Intention to engage in SDM was higher in people randomized to the Video (mean difference [MD] = 0.24 [scale 0-6], 95% confidence interval [CI]: 0.14, 0.35), Questions (MD = 0.12, 95% CI: 0.01, 0.22), and both interventions (MD = 0.33, 95% CI: 0.23-0.44,  < 0.001,  = 0.28) compared with control. Combining interventions had a greater impact than presenting the Questions alone (MD = 0.22, 95% CI: 0.11, 0.32;  < 0.001). Those who received the Video or both interventions reported lower intention to follow the low-value treatment plan without further questioning (all  < 0.05) and more positive attitudes toward SDM (all  < 0.05) compared with control. Intervention acceptability was high in all study arms (>80%), but proactive access was low (1.7%-20.8%). Compared with control, participants who received one or both interventions asked more questions that mapped to the Choosing Wisely questions (all  < .001). There were no main effects of either intervention on self-efficacy or knowledge. CONCLUSIONS: The Choosing Wisely questions and a video to promote SDM may improve intention to engage in SDM and support patients in identifying questions that align with the Choosing Wisely campaign (with some additional benefits of the video intervention). TRIAL REGISTRATION: ANZCTR376477. HIGHLIGHTS: We conducted a randomized controlled trial online with adults living in Australia to test the effectiveness of the consumer Choosing Wisely questions and a shared decision-making (SDM) preparation video.Both interventions improved intention to engage in SDM and supported participants to identify questions that align with the Choosing Wisely campaign.There were some additional benefits of the Video intervention in reducing willingness to accept low-value treatment for low-back pain without asking questions; however, neither intervention changed participants' self-efficacy to ask questions and be involved in decision-making nor affected perceptions of preparedness to engage in SDM or knowledge of rights to be involved in health care decision-making.The simple, low-cost nature of the interventions may make them appropriate for implementation within a suite of approaches to address low-value care at a population level.