Purpose: The purpose of this study was to test the effectiveness of a 12-month restorative care (Res-Care) intervention on the beliefs related to Res-Care, knowledge of Res-Care, observed performance of Res-Care with residents, and job satisfaction among nursing assistants (NAs) in nursing home (NH) settings. Design and Methods: This was a randomized controlled trial including 12 sites and used a repeated measure design with follow-up testing done at 4 and 12 months. An intention-to-treat principle was followed in all analyses, and generalized estimating equations were used to perform repeated measures. A total of 556 NAs consented to participate and completed baseline assessments (265 in treatment and 258 in control sites), 427 completed 4-month follow-up (218 in treatment and 195 in control sites), and 357 completed 12-month follow-up (168 in treatment and 158 in control sites). Results: There was a statistically significant increase in the treatment group participants' outcome expectations related to Res-Care activities (p = 0.04) and performance of Res-Care (p less than 0.001) at 4 months, and an increase in knowledge of Res-Care (p less than 0.001) and job satisfaction (p less than 0.001) at 12 months. There was no difference between the groups with regard to self-efficacy expectations. Implication: This study provides an important step in understanding the implementation of a Res-Care philosophy in NH settings and the benefit this can have for NAs.