Introduction: Over-the-counter (OTC) hearing aids have the potential to improve accessibility and affordability of hearing care. However, limited evidence exists on how individuals make decisions when selecting OTC devices, particularly prior to hands-on experience. Understanding these decision-making factors is critical to inform patient education, device design, and service delivery models. Additionally, documenting user-reported side effects following device use can provide insights into real-world challenges that may influence satisfaction and adherence. This study aimed to examine factors influencing OTC hearing aid choice at baseline and to describe self-reported negative side effects following six months of device use. Methods: Seventy-five adults (mean age = 68.7 years, female=65.3%) completed an OTC hearing aid choice questionnaire as a part of a four-arm randomized clinical trial. Participants identified multiple sources that influenced their decision (e.g., internet websites, consumer reviews, company websites) and rated the extent to which attributes such as hearing aid brand, price, design, manufacturer support, warranty, online reviews, promotional materials, etc. influenced their choice. At six months post-fitting, participants completed the Negative Side Effects of Hearing Aids (NSE-HAs) questionnaire. Quantitative responses were analyzed descriptively, while open-ended responses were analyzed using thematic analysis. Results: Participants primarily relied on internet websites (83%), followed by consumer reviews 1 IHCON 2026 (75%) and company websites (56%) when deciding. Online reviews were the most impactful factor, with 93% reporting moderate to very large impact on their decision-making. Other factors that played a substantial role included perception of manufacturer support (72%), company website (68%), design and appearance (66%), brand/company name (64%), and warranty (57%), while price and promotional advertisements had minimal influence. Qualitative findings (n = 69) supported these results, highlighting reliance on digital information sources and emphasizing technology/connectivity features, perceived sound quality, comfort/fit, and brand trust. Six months post hearing aid usage (n = 41), approximately 30% reported physical side effects (e.g., poor sound quality, sounds uncomfortably loud, feeling plugged/fullness, itching/rashes), and about 40% reported issues such as feedback noise, sounds being too soft, tinnitus, and poor fit as problematic. Conclusion: OTC hearing aid decision-making appears to be largely shaped by digitally sourced information and perceived device attributes prior to use. However, user-reported negative side effects at six months indicate that problematic sound and physical side effects are common. Together, these findings suggest that factors influencing OTC device selection may not fully capture aspects of post-use experience, highlighting the need for clearer consumer guidance on expected benefits and potential challenges.