This paper evaluates the impact of a weekly parenting home-visiting program based on the Reach Up curriculum and a cash transfer, using a randomized controlled trial in Thailand. The targeted children were preschoolers, with an average age of 36 months at the start of the parenting program. The intent-to-treat effect of the 10-month parenting program is positive and significant, with an effect size of approximately 0.13–0.16 SD, whereas the cash transfer is positive but insignificant. Treatment-on-the-treated effects reveal that each home visit improves child outcomes by 0.004 SD. The parenting program is more beneficial for younger and disadvantaged children, as measured by having special needs, less educated parents, lower household wealth, and fewer books at home, whereas the cash transfer is more effective for younger children, children with special needs, and boys.