In this article, we report on the results of a study comparing the preparedness, content knowledge, and instructional practices of elementary science specialist (ESS) teachers with those of a matched sample of self-contained elementary teachers. Analysis of survey data collected for the two groups indicated that ESS teachers were more likely than self-contained teachers to hold science content degrees. ESS teachers scored significantly higher than self-contained teachers on self-reported measures of the following: preparedness to teach science and engineering content; familiarity with science standards; knowledge of students' strengths and weaknesses in science, having enough time to meet students' needs in science and having enough time to plan for all the subject areas that they teach. ESS teachers also scored significantly higher than self-contained teachers on selected measures of science content knowledge. Finally, in comparison to self-contained teachers, some elements of ESS teachers' science lessons were better aligned with our chosen framework for quality elementary science instruction. Regression analyses suggested that these differences in quality of science lessons could be predicted based on the different amounts of time that ESS and self-contained teachers are respectively afforded for planning and teaching science. Implications are provided for future research into elementary science specialization as well as professional development support for all teachers of elementary science.