A pre-post pilot study suggests that the How-to Parenting Program (Faber & Mazlish, 2012) could improve parenting quality (structure, affiliation, autonomy support) and child mental health (Joussemet et al., 2014). However, whether improvements are maintained over time and whether they are reported by all parents remain unclear. In this study, we followed Joussemet et al.’s sample of parents during one year after their program participation. A total of 93 parents of elementary school children reported on their parenting practices and evaluated their children’s externalizing and internalizing problems at pre- and post-test, and again at 6- and 12-month follow-ups. Multivariate multilevel analyses revealed that linear and quadratic trends over the four assessments were significant for all variables, except for affiliation (linear trend only). Affiliation improvements continued to increase over time whereas all other improvements generally occurred before the six-month follow-up and then stabilized (or decreased) from the six-month to the one-year follow-up. Exploratory analyses revealed that only parent gender and child age moderated improvements in some aspects of parenting, but no other moderation was observed. Positive associations between parenting and child mental health change were also observed. These results suggest that the How-to Parenting Program could yield long-term benefits for many families.