The study investigated the effect of play therapy on school adjustment on attention deficit hyperactivity disorder pupils in Port Harcourt Metropolis, Rivers State. This study was guided by three research questions and three null hypotheses. Quasi-experimental research design within which; the Solomon four group design was employed. A purposive sampling technique was used to draw the sample for the study. A sample of 60 primary three pupils who met the criteria for ADHD were randomly assigned into the four groups which was made up of two experimental groups and two control groups. Two valid instruments titled: Conners' Rating Scales-Revised (CRS-R) for assessment of Attention Deficit Hyperactive Disorder and School Adjustment Scale (SAS) were used for collection of data in the study. The validity of instruments was determined using both expert judgment and multivariate statistical method of factor analysis. To ensure the reliability of the instruments for internal consistency, Cronbach alpha was used and reliability coefficients of .78 and .510 were gotten for CRS-R and SAS respectively. Data obtained was analyzed using mean, standard deviation, dependent sample t-test, 2, Analysis of Covariance (ANCOVA) and using One-way analysis of Variance (one-way ANOVA). The results revealed that play therapy (toy and object and role play techniques) is significantly effective in the improvement of school adjustment of attention deficit hyperactivity pupils.