This brief investigates teaching vacancies and difficult-to-staff teaching positions (i.e., positions for which the principals reported that it was very difficult to fill a vacancy or that they could not fill a vacancy in a specific subject area) in public schools in four school years (1999-2000, 2003-04, 2007-08, and 2011-12). This Statistics in Brief uses data from the Public School Questionnaire of the 1999-2000, 2003-04, 2007-08, and 2011-12 Schools and Staffing Surveys (SASS) to examine the percentages of public schools with teaching vacancies and the percentages of public schools with subject areas with difficult-to-staff teaching positions. This brief first presents a picture of teaching vacancies and difficult-to-staff teaching positions overall and by school level (elementary, middle, and high) and then focuses on staffing difficulties in different subjects and by selected characteristics at the high school level. The findings highlighted in these sections are an illustrative rather than exhaustive list of all statistically significant differences found in the study. Study questions include: (1) What percentages of all public schools reported teaching vacancies; What percentages of all public schools reported difficult-to-staff teaching positions; (2) What percentages of public high schools reported difficult-to-staff teaching positions in different subject areas; and (3) How did the percentages of public high schools that had difficult-to-staff teaching positions in zero, one, or two or more subject areas vary by selected school characteristics? Key findings include: (1) Compared to the 1999-2000 school year, a lower percentage of schools had at least one teaching vacancy in the 2011-12 school year (figure 1); (2) In 2011-12, the percentage of schools that had at least one difficult-to-staff teaching position was less than half the percentage in 1999-2000 (figure 1); (3) The percentages of public high schools that reported difficult-to-staff teaching positions were lower in every reportable subject area in 2011-12 than they were in 1999-2000 (table A-3); and (4) In the 1999-2000, 2003-04, 2007-08, and 2011-12 school years, a larger percentage of high-minority than low-minority public high schools had two or more subject areas with difficult-to-staff teaching positions (figure 4). Appended are: (1) Data Tables, and (2) Standard Error Tables.