This study aimed to develop and psychometrically test the managerial competence scale for first-line nurse managers (FLNMs) in Indonesia. The scale was based on items derived from an integrative review and interviews with experts. A total of 300 FLNMs from 16 public hospitals were randomly selected for this test of psychometric properties. A principal component analysis generated seven dimensions with 43 items as a final scale, with overall Cronbach's alpha of .95 while the dimensions' Cronbach's alpha ranged from .71 to .90. The findings demonstrate that the scale is valid and reliable as a vehicle for assessment of managerial competence of FLNMs.