Arrests represent individuals' entry into the public safety system. Increases in arrest rates can be an indication of increased crime, increased enforcement, or both. Disparities in this rate by race or ethnicity can highlight structural differences in how communities are affected and treated by the public safety system. Having been arrested can impact on a person's ability to access employment and other opportunities.

In 2021, Brookline had an arrest rate of 1 per 1,000 white residents, 0.8 for African Americans, and 0.1 per 1,000 for Hispanics and Asian residents. Arrest rates among all groups in Brookline have declined since 2011.

Brookline's 2021 rate among African Americans was lower than Cambridge (3.0) and Everett (1.7). Its rate among Hispanics was second lowest behind Everett and on par with Arlington. Brookline's rates for all groups were lower than the state.

Disparities in adult arrests are the result of racialized stereotypes, policies and practices and community conditions. Stereotypes that portray Black and Latino people, especially males, as inherently dangerous, criminal, and violent lay the foundation for police surveillance and disparate and harsher treatment by the criminal justice system. Communities of color are more likely to be under surveillance and policies such as stop and frisk perpetuate increased police contact. Punitive drug laws have had disproportionate impact on Black and Latino communities. Even though Blacks and whites have similar rates of drug use, Black people are more likely to be arrested and experience harsher sentences. The concentration of Black and Latino communities in highly segregated communities with limited economic opportunities and ineffective schools may also foster crime involvement.

Comparable national data is not available.