Recently, the HEAR-aware app was developed to support adults who are eligible for hearing aids (HAs) but not yet ready to use them. The app serves as a self-management tool, offering assistance for a range of target behaviors (TBs), such as communication strategies and emotional coping. Using ecological momentary assessment and intervention, the app prompts users to complete brief surveys regarding challenging listening situations they encounter in their daily lives (ecological momentary assessment). In response, users receive educational content in the form of "snippets" (videos, texts, web links) on the TBs, some of which are customized based on the reported acoustic environmental characteristics (ecological momentary intervention). The primary objective of this study was to assess the effectiveness of the HEAR-aware app in enhancing readiness to take action on various TBs and evaluate its impact on secondary outcomes. The secondary objective was to examine the app's usability, usefulness, and user satisfaction. A randomized controlled trial design with two arms was used. Participants with hearing loss aged 50 years and over were recruited via an HA retailer and randomly assigned to the intervention group (n = 42, mean age = 65 years [SD = 9.1]) or the control group (n = 45, mean age = 68 years [SD 8.7]). The intervention group used the app during 4 weeks. The control group received no intervention. All participants completed online questionnaires at baseline (T0), after 4 weeks (T1), and again 4 weeks later (T2). Participants' readiness to take action on five TBs was measured with The Line Composite. A list of secondary outcomes was used. Intention-to-treat analyses were performed using Linear Mixed effect Models including group (intervention/control), time (T0/T1/T2), and Group × Time Interactions. In addition, a per protocol analysis was carried out to explore whether effects depended on app usage. For the secondary aim the System Usability Scale (SUS), the Intrinsic Motivation Inventory, item 4 of the International Outcome Inventory-Alternative Intervention (IOI-AI), and a recommendation item were used (intervention group only at T1). For objective 1, there was no significant group difference for The Line Composite over the course of T0, T1, and T2. However, a significant (p = 0.033) Group × Time Interaction was found for The Line Emotional coping, with higher increase in readiness to take action on emotional coping in the intervention group than in the control group. The intention-to-treat analyses revealed no other significant group differences, but the per protocol analyses showed that participants in the intervention group were significantly more ready to take up Assistive Listening Devices (The Line Assistive Listening Devices) and less ready to take up HAs (Staging Algorithm HAs) than the control group (p = 0.049). Results for objective 2 showed that on average, participants rated the app as moderately useful (mean Intrinsic Motivation Inventory score 5 out of 7) and its usability as "marginal" (mean SUS score 68 out of 100) with about half of the participants rating the app as "good" (SUS score >70) and a minority rating is as "unacceptable" (SUS score ≤50). This study underscores the potential of self-management support tools like the HEAR-aware app in the rehabilitation of adults with hearing loss who are not yet ready for HAs. The range in usability scores suggest that it may not be a suitable intervention for everyone.