This longitudinal research identified the developmental trajectories of sibling jealousy in firstborn children (M age = 49.9 months; 55% boys) among 107 Chinese families from 1 to 12 months after the birth of a younger sibling. Four sibling jealousy trajectories were identified: (a) low-increasing, (b) middle-stable, (c) high-stable, and (d) sharp-increasing. Trajectory group membership varied as a function of pre-birth parental factors including strict parental control (i.e., tiger parenting), parenting stress, and parental depression. These results highlight the benefit of examining the development of sibling jealousy over the transition to siblinghood and the importance to recognize pre-birth parental characteristics, especially paternal factors, as determinants when identifying children who may be at greater risk of adjustment difficulties following the birth of a younger sibling.