This research investigated the internal and external barriers teachers encounter when planning for and implementing problem-based learning (PBL) in the middle school classroom. Barriers occurring in the middle school studied were defined through the use of classroom observations, teacher surveys, and interviews with teachers and administrators. Based on the results of data analysis, barriers such as lack of feedback, rewards and incentives for PBL implementation and misalignment of vision between teachers and administration created difficulties for teachers trying to plan and implement a PBL unit. From these results appropriate performance interventions were selected and proposed to help teachers overcome the internal and external barriers. Theoretical Framework According to Market Data Retrieval (MDR, 2002) schools in the United States have, on average, a student-computer ratio of 4 to 1, and 98% of schools and 77% of classrooms have Internet access. Recent demographic data from the Integrated Studies of Educational Technology (ISET; U.S. Department of Education, 2003) showed that 81% of teachers have either moderate or high levels of access to instructional computers. Yet, despite these high levels of access, the integration of technology into our schools has been less successful than anticipated. Meaningful technology use tends to align with a constructive teaching philosophy (Berg, Benz, Lasley, & Raisch, 1998) and student-centered learning beliefs (Becker & Riel, 1999). According to Sage (2000), a problem-based learning (PBL) approach can provide a meaningful and effective way to integrate technology into the classroom. Because PBL uses ill-structured problems to provide opportunities for student learning, technology is a critical tool for information searching, modeling task or content decisionmaking, and presenting solutions. As a result, technology-enhanced PBL can be a meaningful learning experience (Ertmer, Lehman, Park, Cramer, & Grove, 2003; Jonassen, Howland, Moore, & Marra, 2003). There are many reasons why teachers have not embraced technology-enhanced PBL to its full potential including lack of preparation time, limited resources, lack of administrative support, and limited class time to implement PBL in the curriculum (Park, Cramer, & Ertmer, 2004). Other reasons are that teachers may have difficulty adjusting to a more guiding role and helping students to become more selfdirected (Brinkerhoff & Glazewski, 2004; Brush & Saye, 2000; Land, 2000). These external and internal barriers, as explored by Ertmer, Addison, Lane, Ross and Woods (1999), have different characteristics.