This research investigated the immediate and long-term effects of a Tier 2 intervention for beginning readers identified as having a high probability of reading failure using a randomized control trial. First-grade participants (n = 123) were randomly assigned either to a 25-session intervention targeting key reading components, including decoding, spelling, word recognition, fluency, and comprehension, or to a no-treatment control condition. Analyses of immediate posttests (end of first grade) indicated significant differences in measures of Decodable Word Fluency (effect size = 0.40) favoring the intervention group. Within the intervention group, tutor ratings of attention were significantly related to growth in Passage Reading Fluency and Spelling Fluency. Longitudinal assessments (end of second grade) indicated no significant differences by group. Analysis of responder status indicated that students defined as responders maintained gains to the end of second grade.