Autistic students often experience peer relationship difficulties. As peer acceptance and rejection may be malleable over time, we examined predictors of change in peer acceptance and peer rejection among early elementary-age autistic students. We followed 166 autistic children (mean age: 6.1 years [range: 4-8], 82.5% boys, grades preK-2nd) longitudinally across 2 school years. Social skills, internalizing problems, and externalizing behaviors were considered as predictors of change in teacher-rated peer acceptance and rejection, covarying IQ and autism characteristics. Autistic children experienced high rejection and low acceptance; 51.9% of children were rejected by peers in one or both school years. Results revealed distinct predictors for peer acceptance versus rejection: social skills predicted change in peer acceptance across school years, whereas externalizing problems predicted change in peer rejection. Internalizing problems did not predict change in either construct. Findings can assist school professionals in supporting social acceptance and acceptance for young autistic students. [For the corresponding Grantee Submission, see ED621597.]