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.