The study examined climate change knowledge and the adoption of green practices forsustainability among academic libraries in the Federal Capital Territory, Nigeria. Adopting adescriptive survey design of a correlational type, the study employed total enumerationsampling, yielding 165 valid responses from librarians across universities, polytechnics, andcolleges of education in the FCT. Data were collected through a structured questionnaireadministered both online (via Google Forms) and in person. Findings revealed that while e-resource adoption (86.1%), natural ventilation (81.8%), and energy-efficient lighting (71.5%)were widely implemented, capital-intensive measures such as rainwater harvesting (29.7%)and solar-powered devices (35.2%) remained largely unadopted. Library personneldemonstrated a high level of climate change knowledge (aggregate mean = 3.23 on a four-point scale), with the strongest scores in energy conservation (M = 3.44) and greenhouse gasawareness (M = 3.41), and comparatively lower scores in knowledge of environmental policies(M = 2.98). The primary barriers to green practice adoption were inadequate funding (M =3.44), unstable power supply (M = 3.41), and insufficient technology availability (M = 3.29).Pearson correlation analysis confirmed a statistically significant moderate positiverelationship between climate change knowledge and green practice adoption (r = .360, p =.002, r² = .130), indicating that knowledge accounts for approximately 13% of the variance ingreen practice adoption. The null hypothesis was rejected. These findings indicate the need fortargeted climate literacy programmes, formal sustainability policies, and institutional resourceallocation to bridge the gap between knowledge and practice in Nigerian academic libraries.