Measures of parents' cognitions have advanced our understanding of infants' sleep. But, few comparable measures exist for use with parents of preschool- or school-age children. The Parents' night-waking thoughts and affect questionnaire (PNTQ), a self-report measure of parents' thoughts and feelings when their children wake during the night, addresses this need. This scale was evaluated in two community samples of parents (N = 473). Sample 1 included preschool-age children (2-5-years-old), and Sample 2 included preschool- and school-age children (2-10-years-old). A subsample completed 1-month test-retest reliability for the PNTQ (n = 201). Parents completed the PNTQ and measures of agreement with night-waking strategies, parenting stress, mental health, and night-waking. The psychometric properties of the PNTQ (i.e., internal consistency, test-retest reliability; content, construct, and convergent validity) were evaluated. A four-factor solution (positive thoughts about limit-setting, positive thoughts about active comforting, concerns about limit-setting, and distress about night-waking) demonstrated adequate fit in Sample 1 (robust CFI = .900; robust RMSEA = .060), which was replicated in Sample 2 (robust CFI = .870; robust RMSEA = .080). Internal consistency (αc = .68-.88) and test-retest reliability (r = .46-.80) were acceptable across subscales and samples. There was good evidence for convergent validity in both samples-including correlating with parent-reported night-waking behaviour. The PNTQ is a promising measure of thoughts and affect related to night-waking experienced by parents whose children wake during the night. The PNTQ may increase understanding of parents' use of specific night-waking strategies and may account for resistance to employing alternate techniques. (PsycInfo Database Record (c) 2022 APA, all rights reserved).