Although some research-based educational practices have shown promise, many fail to be implemented at a scale that affects more than a small proportion of children. Further, research on interventions for young children includes mixed results, with most documenting "fadeout" of effects after several years, but some showing lasting effects. In this study, the authors evaluated the long-term impacts of a model for scaling up early interventions, in this case a successful early mathematics curriculum, testing to see whether the originally-sustained impacts persisted up to 7 years beyond baseline. The original evaluation of TRIAD (Technology-enhanced, Research-based, Instruction, Assessment, and professional Development) employed a cluster randomized trial (CRT) design to test the effectiveness of the TRIAD scale-up approach, using the Building Blocks® early mathematics curriculum (BB) in preschool. In this evaluation, 42 schools were randomly assigned to three groups. One of the groups was a business-as-usual control (CTRL). In preschool, the other two conditions were identical and entailed TRIAD scale-up (intensive training, coaching focused on both BB curriculum and linked assessment and online professional development). After preschool, one of the treatment conditions included follow-through professional development through 1st grade, including knowledge of the intervention and ways to build upon that knowledge using learning trajectories (TRIAD Follow-Through or TRIAD-FT) while the other condition implemented business-as-usual control (TRIAD Non-follow-through or TRIAD-NFT). Students in the two treatment conditions significantly outperformed their peers in the control condition through 1st grade. The primary purpose of the current investigation was to examine the long-term effects of the early mathematics curriculum, but the secondary aim was to explore whether the TRIAD scale-up approach itself, which included aligned professional development for kindergarten and 1st grade teachers, also enhanced the effects of the pre-K curriculum beyond 1st grade. Research questions were as follows: (1) What are the differences in the average math achievement of the three original study groups (TRIAD-NFT, TRIAD-FT, and CTRL) in 3rd, 4th, and 5th grade; (2) Do the differences in the 3rd, 4th, and 5th grade math achievement of the original study groups vary by the socio-economic and racial/ethnic backgrounds of the students in the groups; (3) What are the differences in the 3rd, 4th, and 5th grade math achievement of the subset of children who remained in the group to which their original school was randomly assigned throughout the intervention period (pre-K through 1st grade); and (4) Do the differences in the in the 3rd, 4th, and 5th grade math achievement of the subset of children who remained in the group to which their original school was randomly assigned throughout the intervention period (pre-K through 1st grade) vary by the students' socio-economic status and racial/ethnic backgrounds? Figure 1 presents results addressing the first research question that pertain to the differences between the three groups at the end of pre-K through 5th grade. Figures 2a and 2b inform the second research question and show the effects of the FT and NFT conditions separately for African-American, Hispanic, other minority, and white students. Figures 3a and 3b show the FT and NFT effect estimates separately for the low and high SES subgroups formed based on students' eligibility for FRPL. Figures 4, 5a, 5b, 6a, and 6b inform the 3rd and 4th research questions and show parallel results for the stayers (students who stayed in the original conditions between pre-K and 1st grade). Impacts at the end of 5th grade were statistically significant and considerably larger than impacts in 3rd and 4th grade for both conditions and all subgroups. Tables and figures are appended.