This study examines the effects of legislatively mandated changes in terminology for National Health Interview Survey (NHIS) questions on proxy and self-reports of an important condition. Specifically, we examine changes from the use of the term “mental retardation” to “intellectual disability” that were mandated by what is now known as “Rosa’s Law,” an act signed by President Obama in October 2010. Our analyses focus on changes in national prevalence of measures of intellectual disability during the period 2011–2016, compared to 1997–2010, for the population as a whole and for demographic subgroups. Findings show that the change in question wording implemented in the NHIS after Rosa’s Law produced a small, albeit statistically significant, increase in reporting of intellectual disabilities for adults and for children.