Purpose: This study aimed to investigate the relationship between the expectations of unit-level nurses from nursing assistants (NAs), frequency of individual NAs' information-sharing behaviors with nurses, and the effect of NAs’ self-perceived roles on this relationship. NAs provide patient care along with nurses, and their information-sharing behaviors with nurses may be influenced by the expectations of the nurses. Methods: Nurses and NAs from 104 integrated community care (sub- and postacute) units were included in this Japanese cross-sectional study conducted from July to September 2018. Nurses' expectations from NAs and the NAs' self-perceived roles and information-sharing frequency were measured. Multilevel mediation analysis was performed for NAs’ information-sharing behaviors, such as expressing, asking, providing linguistic responses, and providing feedback. Results: Unit-level nurses' expectations from NAs were associated with the frequency of NAs' asking and responding behaviors with nurses (p < .05), mediated by the NAs' self-perceived roles. The frequency of NAs’ expressing behaviors and feedback were also associated with their self-perceived roles (p < .001). Conclusions High expectations of unit-level nurses from NAs led to better perception by NAs of their roles and led to better information-sharing behaviors. Educating nurses on NAs’ roles may improve information-sharing between nurses and NAs that leads to safe and appropriate care to patients.