With an increasing percentage of schools moving toward approaches to data-based instructional problem-solving and early remediation of learning difficulties, the development and execution of intervention plans often warrants the pragmatic question: How intensive should an intervention be so that it is effective, while also feasible and time efficient to implement? In other words, educators must prudently balance treatment intensity, anticipated effectiveness, and available implementation resources. This study examined the effects of an evidence-based reading fluency intervention that included the same instructional components but was implemented with varying treatment durations and student-teacher ratios. Using an alternating-treatments design, four second-grade struggling readers received four treatment conditions (small group with ~14 min of intervention; small group with ~7 min of intervention; one on one with ~14 min of intervention; and one on one with ~7 min of intervention) and a no-intervention control condition. Using three data-analytic strategies and two dependent measures, overall findings suggested that all intervention conditions led to reading improvements but that (a) the longer intervention duration appeared more effective than the shorter duration, and (b) there was little difference in intervention effectiveness between the small-group and one-on-one conditions.