Increasing emphasis is being placed on providing educational interventions for children with learning and behavioral problems in the least restrictive environment (LRE). This results in greater pressure on teachers, who have often had little or no specialized training in classroom management and individualized educational needs. Efforts to assist teachers working with students having difficulty usually involve teachers using a problem-solving process to develop individualized interventions. However, little applied research has been conducted to confirm the critical factors important in developing and implementing interventions to achieve positive student outcomes in school settings;Several factors suggested as important in intervention implementation include intervention acceptability, integrity, and effectiveness. Both intervention acceptability and integrity are hypothesized to influence intervention implementation and effectiveness. Most school-based intervention plans do not include assessment of these factors. Little research has been completed to examine interventions in applied settings to determine if the hypothesized relationship between the components exists;The overall purpose of this project was to assess the relationships between intervention acceptability, intervention integrity, and the effectiveness of classroom interventions using two studies. The first study involved observing interventions as they were implemented in elementary classroom settings. The second study used a survey to ask elementary teachers in 11 states about their experiences and perceptions of interventions they have implemented for students;Findings from both studies indicated that teachers tended to receive assistance when developing the interventions, but then implemented the interventions alone. In general, individualized interventions plans did not describe the specific steps to be completed as part of the intervention. In both studies, most teachers rated the interventions that they implemented from moderate to very acceptable. Implementation integrity was found to be high in the observation study. Teachers in the survey indicated more use of formal efforts to maintain intervention integrity than did teachers in the observation study. Further findings and implications are also discussed.