The whole-school approach is difficult to evaluate since a large number of complex components must be considered and all target groups must be included. Some evaluation studies do, however, show promising results indicating that a whole-school approach can positively impact staff development and the social climate of school and in some cases also positively influence health behaviors like healthy eating and physical activity (ListerSharp et al., 1999; Stewart-Brown, 2006). Most interventions addressing improvement of health promoting behaviors are also found to be more promising when they include a whole-school approach rather than solely a health education classroom approach (ListerSharp et al., 1999). This applies to school-based mental health interventions (Wells, 2001; Licence, 2004) as well as physical activity and healthy eating programs. Physical activity interventions that include changes to the environment as well as organized recess activities seem more efficient than those that mostly use a curriculum approach through physical education (Sallis et al., 2003; Jago and Baranowski, 2004). Similarly, access to and availability of fruit and vegetables in the school setting is found to be of higher importance than changing attitudes in influencing eating behaviors (Blanchette and Brug, 2005). Since little systematic evidence about the effectiveness of health-promoting, whole-school approaches on changing any single behavior exists, program evaluation becomes highly important for the developing field. Thus far, theory-driven programs have proven most successful. Many leading scholars therefore recommend that new programs be built on strong theoretical foundations. Another important aspect to consider in evaluation of school health promotion programs is which parameters are the best measures of effectiveness. Thus far, health behaviors, health perceptions, and subjective well-being have been used as measurement of program effectiveness. However, the 1to 3-year timelines of program implementation are short-term and may make relevant behavioral changes difficult to capture. Even more challenging are assessments of changes in school environments in the whole-school approach. Such complex, large-scale changes may take 6–8 years to achieve and identify (Green and Kreuter, 1999). Thus, two critical aspects must be considered. First, in short-term health promotion programs, changes in intermediate factors anticipated to influence health behaviors, health, and subjective well-being should be included as measures of effectiveness. Second, implementation time for school health programs should be extended. This, of course, also requires taking the long view when crafting the length of the funding scheme used to support the changes. Whole-school health promotion programs should be followed for at least 5–10 years, in order to identify and assess in adequate and rigorous ways the impact of the school environment changes on health behavior, health, and subjective well-being among students and staff.