Introduction The rapid adoption of telehealth services due to the COVID-19 pandemic has highlighted the necessity for effective tools to evaluate patient experiences. This study developed and validated the Telehealth Usability, Acceptability, and Satisfaction Questionnaire (TUASQ) for virtual COVID-19 Assessment Centres (CACs) in Malaysia, aiming to comprehensively measure usability, acceptability, and satisfaction. Methodology The TUASQ was developed in two phases. Initially, the questionnaire development phase included item generation guided by the Technology Acceptance Model (TAM) and the Health Belief Model (HBM), with feedback from a panel of six experts. Items were refined through Content Validity Index (CVI) - Item-Level Content Validity Index (I-CVI) ≥ 0.82, Scale-Level Content Validity Index (S-CVI) ≥ 0.82, and Content Validity Ratio (CVR ≥ 0.78); and Face Validity Index (FVI) by 10 respondents - Item-Level Face Validity Index (I-FVI) ≥ 0.82and Scale-Level Face Validity Index (S-FVI ≥ 0.82). The psychometric validation phase involved a cross-sectional study of 705 respondents, recruited through convenience sampling from March to July 2024, to perform Exploratory Factor Analysis (EFA) and Confirmatory Factor Analysis (CFA), followed by reliability testing using Cronbach's alpha, Composite Reliability (CR), and Average Variance Extracted (AVE). Results Content validation showed that most items' I-CVI exceeded 0.82, indicating significant expert consensus on relevance and clarity. The CVR also surpassed the 0.78 threshold, affirming their essential role. Face validation indices generally exceeded 0.80, confirming the questionnaire's clarity and comprehensiveness from the users' perspective. EFA with 250 participants indicated a high Kaiser-Meyer-Olkin Measure of Sampling Adequacy (KMO) of 0.933 and significant Bartlett's test (χ² (136) = 3752.698, p < 0.001), supporting the factorability of the data and extracting three distinct factors. CFA with 455 participants initially showed a poor fit, prompting model adjustments that subsequently improved the fit indices (Root Mean Square Error of Approximation (RMSEA) = 0.076, Standardized Root Mean Square Residual (SRMR) = 0.045, Goodness of Fit Index (GFI) = 0.94, Tucker-Lewis Index (TLI) = 0.96, Comparative Fit Index (CFI) = 0.97). Reliability testing revealed a high internal consistency with Cronbach's alpha of 0.975. CR for each factor exceeded the 0.70 threshold, and the AVE for each factor was above 0.50, indicating good convergent validity. Conclusion The validated TUASQ is a reliable and effective instrument for assessing the experiences of Malaysian patients using virtual CAC. Demonstrating robust psychometric properties through comprehensive validation processes, the TUASQ accurately measures usability, acceptability, and satisfaction, identifying strengths and areas for improvement in telehealth services. This contributes to enhanced care quality and patient satisfaction in the evolving healthcare landscape.