Caregivers have been largely neglected in health literacy measurement. We assess the construct validity, and internal consistency of the Health Literacy of Caregivers Scale-Cancer (HLCS-C), and present a revised, psychometrically robust scale. Using data from 297 cancer caregivers (12.4% response rate) recruited from Melbourne, Australia between January-July 2014, confirmatory factor analysis (CFA) was conducted to evaluate the HLCS-C's proposed factor structure. Items were evaluated for: item difficulty, unidimensionality and overall item fit within their domain. Item-threshold-ordering was examined though one-parameter Item Response Theory models. Internal consistency was assessed using Raykov's reliability coefficient. CFA results identified 42 poorly performing/redundant items which were subsequently removed. A 10-factor model was fitted to 46 acceptable items with no correlated residuals or factor cross-loadings accepted. Adequate fit was revealed (χ2WLSMV = 1463.807[df = 944], p < .001, RMSEA = 0.043, CFI = 0.980, TLI = 0.978, WRMR = 1.00). Ten domains were identified: Proactivity and determination to seek information; Adequate information about cancer and cancer management; Supported by healthcare providers (HCP) to understand information; Social support; Cancer-related communication with the care recipient (CR); Understanding CR needs and preferences; Self-care; Understanding the healthcare system; Capacity to process health information; and Active engagement with HCP. Internal consistency was adequate across domains (0.78-0.92). The revised HLCS-C demonstrated good structural, convergent, and discriminant validity, and high internal consistency. The scale may be useful for the development and evaluation of caregiver interventions.