The developmental trajectories of maladaptive perfectionism, along with their consequences and origins, were examined in middle childhood. A sample of Singaporean children and their parents (N = 302) were recruited for a longitudinal study when the children were 7 years old. Subsequent follow‐up assessments were made at ages 8, 9, and 11. A multimethod approach was adopted where parent reports, child reports, and observational data on a dyadic interaction task were obtained. Using latent class growth modeling, four distinct classes were obtained for critical self‐oriented perfectionism (SOP‐C), whereas two classes emerged for socially prescribed perfectionism (SPP). Children with high and/or increasing SOP‐C and SPP trajectories constituted 60% and 78% of the sample, respectively. For both SOP‐C and SPP, trajectories with high initial status were associated with higher internalizing and externalizing symptoms. Parental intrusiveness and negative parenting predicted high and/or increasing SOP‐C trajectories, whereas the child temperament dimension of surgency predicted high SPP trajectory. Both SOP‐C and SPP trajectories tended to co‐occur, suggesting a mutually reinforcing process. This study yields important findings that help advance current understanding of the emergence and developmental pathways of maladaptive perfectionism in children.