Academic Problems
As kids move up into the higher grades, work becomes more challenging and problems are more likely to surface. Without proper supports, students can become easily frustrated and overwhelmed. If school becomes a place where kids feel unsuccessful, they may want to avoid it altogether. Unfortunately, school avoidance in these types of situations usually only makes matters worse, as more class time is missed and grades continue to slip. To combat this problem, be sure to analyze a truant student’s academic record to assess whether or not additional in school academic supports can be provided.
Mental Health Issues
School truancy problems may be a red flag to a more serious problem. More kids than ever are suffering from problems such as anxiety, depression, and substance abuse. These problems can impact with a students’ ability to get themselves to school each morning. Undiagnosed and untreated, these problems can interfere with a student’s overall functioning. If students show symptoms of these problems, a school student assistance or crisis team may be able to intervene and provide some direction.
Family Dynamics
Unfortunately, not all students arrive at school well-rested, well-fed, and ready to start their day. Many students homes are chaotic, some even dysfunctional, and this may impact student’s ability to attend school regularly. Being able to get to sleep at a reasonable hour, get up on time, get ready, and leave in time for school are critical for school attendance and may be difficult in a family that is in crisis. Some students may also be reluctant to leave ill or unstable family members at home alone, or may be used to care for younger siblings or otherwise help out at home during school hours. Families may need help accessing social agencies that can help with some of these issues.
Social Problems
Many students experience social problems, such as bullying or isolation, in school on a regular basis. Fear and shame may cause them to avoid the environment that creates these feelings. These kids may need support in learning social skills or help accessing resources to report and stop bullying. Other students may have friends, but lack a true connection to the larger school community. They may not see themselves as excelling in athletics, music, academics, or any of the other areas schools tend to focus on. For these students, finding a niche where they feel successful, is key.
http://at-risk-youth-support.suite101.com/article.cfm/student_truancy_causes_and_solutions

i totally agree with what aliza has post. i found an interesting article and the causes they given is almost same as eliza's has found however in my opinion the most common factor of trauncy is academic problem. in the article above. it says students play traunt as they cant understand the subject or when they find difficulties in any subject they wont take any insiative t ask teachers and the teacher itself dont bother to know whether everyone i the class understood wat she taught in the class. therefore, once the student fail to understand the previous topic, it will be hard for him to understand the rest of the topics.therefore, once the interest gone, students will start involving in social problem like the most common one is playign truant. besides that, the lack of interest in studies like what eliza han mentioned may be because the method the teacher uses in class to teach the student not interesting enough. the other reason which i think is also very common is social problem. normally it happens in boarding school like bullying, ragging and stuff. all these social problem will make student afraid to come school!
zainab bt ibrahim