A common assumption underpinning health communications design in humanitarian settings is that increasing knowledge and risk perception will lead to appropriate behaviour change. This study compares associations of HIV knowledge and perceived risk with reported HIV-avoidant behaviour changes and sexual health choices from a community survey of 698 sexually experienced male and female Sierra Leonean refugees in Guinea. HIV knowledge was not significantly associated with reported HIV-avoidant changes (OR 1.25; adjusted for gender; 95%CI 0.76-2.04), while perceived HIV risk was negatively associated (OR 0.38, adjusted for age at sexual debut; 95%CI 0.22-0.66). Trying to conceive was the main reason reported for not using condoms or other contraception (28%; 138/498), followed by current pregnancy/lactation (19%; 93/498). Results suggest contextual factors (e.g. desire for children) can be as important as knowledge and risk-perception, and HIV prevention initiatives in stable and chronic humanitarian settings should account for these.