In an effort to understand teachers' perceptions of best practices for treatment of students with attention-deficit/hyperactivity disorder (ADHD) and how those may have shifted over the past 20 years, general education elementary school teachers completed surveys regarding their opinions of evidence-based interventions in the classroom. Two independent and anonymous samples of general education, elementary school teachers were collected: One in 1999 (n = 598) and a second in 2019 (n = 661). Teachers responded to questions about their interactions with students with ADHD as well as their beliefs about best practices for these students. Across survey samples, teachers generally agreed that behavioral classroom management, medications, and the combination of the two are effective treatments for students with ADHD. Comparisons of the 1999 and 2019 survey samples suggest that teachers in 2019 perceive the use of behavioral classroom management somewhat less favorably than did teachers in 1999. Teacher perceptions of best practices for students with ADHD in 1999 and 2019 were generally consistent with professional practice guidelines. Teacher responses also highlight a critical need for training and support related to evidence-based strategies for students with ADHD in the classroom.