The main objective of this systematic review was to examine the effects of interventions on school attendance to inform policy, practice, and research. The questions guiding this study were: (1) Do truancy programs with a goal of increasing student attendance for truant youth affect school attendance behaviors of elementary and secondary students with chronic attendance problems?; (2) Are there differences in the effects of school-based, clinic/community-based, and court-based programs?; and (3) Are some modalities (i.e., family, group, multimodal) more effective than others in increasing student attendance? A systematic and comprehensive search process was employed to locate all possible studies between 1990 and 2009, with every effort made to include both published and unpublished studies to minimize publication bias. A wide range of electronic bibliographic databases and research registers was searched, websites of relevant research centers and groups were mined for possible reports, over 200 e-mails and letters were sent to programs listed in large databases of truancy programs compiled by the National Center for School Engagement and the National Dropout Prevention Center, and contact with researchers in the field of truancy and absenteeism was attempted. In addition, the authors examined reference lists of all previous reviews as well as citations in research reports for potential studies. Overall, the findings from this study suggest that chronic truant students benefit from interventions targeting attendance behaviors; thus it is important and worthwhile to intervene with chronic truant youth. Given the minimal differences in effects across program types and modalities, no one program type or modality stands out as being more effective than any other. Although no statistically significant differences in effects were found between types and modalities of interventions included in this review, there was a lack of available evidence to support the general belief (and popular "best-practice" recommendations) that collaborative and multimodal interventions are more effective than programs that are not collaborative and single modal interventions. Due to the small sample size and large heterogeneity between studies and within groups of studies, caution must be used when interpreting and applying the findings from this meta-analysis. Overall, the studies included in the review improved attendance by an average of 4.69 days, almost a full school week. However, although the interventions included in this study were, overall, found to be effective, the mean rates of absenteeism at posttest in most studies remained above acceptable levels. This finding indicates the need for additional work and research. Developing more effective interventions and policies as well as studying outcomes of interventions, particularly with vulnerable and at-risk populations, is crucial to combating absenteeism. The gaps and deficiencies identified in this study also affirm the need for increasing and strengthening the evidence base on which current policies and practices rest. Although additional outcome research is necessary, more of the same is not sufficient. Significant improvements in the quality of truancy intervention research are required and identified gaps need to be addressed. Recommendations to improve the quality and fill gaps in truancy intervention research are discussed here. In addition, given the significant and pervasive deficiencies in the extant research, a critical analysis of the practices, assumptions, and sociopolitical contexts underlying truancy intervention research seems warranted. Appended are: (1) Included Studies; (2) Excluded Studies; (3) Summary of Included Randomized and Quasi-Experimental Studies; (4) Bivariate Correlation Matrix of Study Characteristics: RCT/QED Studies; (5) Summary of Included Single-Group Pre-Post Studies; and (6) Bivariate Correlation Matrix of Study Characteristics: SGPP Studies. (Contains 14 tables and 3 figures.) [Additional funding for this paper was provided by the Arthur J. Schmitt Foundation.]