Although criminal defendants are constitutionally entitled to be represented by a lawyer, those who are defendants in a civil case or who wish to initiate a civil case do not have the right to representation. Therefore, those who do not have the funds to hire a lawyer may find it difficult to obtain justice.

To deal with this problem, legal aid services are now found in many areas. Legal aid societies were established in New York and Chicago as early as the late 1880s, and many other major cities followed suit in the 20th century. Although some legal aid societies are sponsored by bar associations, most are supported by private contributions. Legal aid bureaus also are associated with charitable organizations in some areas, and many law schools operate legal aid clinics to provide both legal assistance for the poor and valuable training for law students. In addition, many lawyers provide legal services "pro bono publico" (Latin for "for the public good") because they see it as a professional obligation.