The present study aims to understand children's behavior within classroom settings in terms of conditioning theories. It was designed based on grounded theory. Data were collected through participant observation and 98 children whose ages varied between 6 and 10 years were observed. Data were inductively analyzed. Findings indicated that kindergarteners and first graders tend toward classical conditioning and need more teacher control to adjust to classroom settings, whereas children aged from 9 to 10 years behave based on operant conditioning. It is proposed that differences in conditioning stem from teachers' classroom management strategies, and cognitive development.