Young students at risk for reading difficulties are likely to have long-term reading difficulties if they are not provided with evidence-based, supplemental instruction. This pilot study evaluated the feasibility of a Tier 2 reading intervention ("Reading RULES! Kindergarten;" RRK) and its promise to improve outcomes for kindergarten students (n = 92) at risk of reading difficulties. Participating teachers (n = 21) were randomly assigned to deliver RRK or business-as-usual instruction. Although the results suggest null treatment effects, the intervention appears to have promising effects on students' word-reading skills when implemented with sufficient dosage. However, most teachers in the study struggled to implement the intervention with sufficient dosage and adherence, citing systems-level barriers to implementation such as insufficient time. The results suggest teachers may need more systems-level support to ensure the intensity of instruction required to improve the early reading skills of students at risk for reading difficulties.