This study aimed to determine the factors that predict anosognosia in patients with Alzheimer's disease (AD) and to examine the effect of anosognosia on patient and caregiver perceptions of the patient's quality of life (QoL-p), using a cross-sectional design with 164 patients and their caregivers. Instruments of measurement included Anosognosia Questionnaire-Dementia, Geriatric Depression Scale, Quality of Life in AD (QoL-AD), Disability Assessment for Dementia, Neuropsychiatric Inventory, and the Global Deterioration Scale (GDS). A binary logistic regression analysis was performed to identify the factors that predict anosognosia, while a linear regression analysis was conducted to determine the factors associated with QoL-AD. The degree of anosognosia increased in line with GDS stage (F (2,161) = 41.3, p < 0.001). In the binary regression analysis, the variables that predicted anosognosia were more neuropsychiatric symptoms (OR = 1.11, 95% CI: 1.06-1.17, p < 0.001), deficits in ADL (OR = 0.88, 95% CI: 0.83-0.94, p < 0.001), less depression (OR = 0.66, 95% CI: 0.54-0.82, p < 0.001), and older age (OR = 1.08, 95% CI: 1.00-1.15, p = 0.027). With regards to QoL-p, the multiple linear regression analysis for patients (r2 = 0.486) showed that less depression (β = -0.52, p < 0.001) and greater anosognosia (β = 0.40, p < 0.001) explained 33% and 10% of the variance in QoL-AD, respectively. Greater anosognosia was associated with better perceived QoL-p, especially in advanced GDS stages. Anosognosia was associated with greater caregiver burden and a greater discrepancy between patient and caregiver ratings of QoL-p.