Purpose: In this initial article of the clinical forum on reading comprehension, we argue that reading comprehension is not a single ability that can be assessed by one or more general reading measures or taught by a small set of strategies or approaches. Method: We present evidence for a multidimensional view of reading comprehension that demonstrates how it varies as a function of reader ability, text, and task. The implications of this view for instruction of reading comprehension are considered. Conclusion: Reading comprehension is best conceptualized with a multidimensional model. The multidimensionality of reading comprehension means that instruction will be more effective when tailored to student performance with specific texts and tasks.