Background In September 2014, wound clinic A reported a cluster of group A Streptococcus (GAS) infections to public health authorities. Although clinic providers were individually licensed, the clinic, affiliated with hospital A, was not licensed or subject to regulation. We investigated to identify cases, determine risk factors, and implement control measures. Methods A case was defined as GAS isolation from a wound or blood specimen during March 28-November 19, 2014, from a patient treated at wound clinic A or by a wound clinic A provider within the previous 7 days. All wound clinic A staff were screened for GAS carriage. Wound care procedures were assessed for adherence to infection control principles and possible GAS transmission routes. Results We identified 16 patients with 19 unique infections: 9 (56%) patients required hospitalization, and 7 (44%) required surgical debridement procedures. One patient died. Six (37%) patients received negative pressure wound therapy at GAS onset. Staff self-screening found no GAS carriers. Breaches in infection control and poor wound care practices were widespread. Conclusions This GAS outbreak was associated with a wound care clinic not subject to state or federal regulation. Lapses in infection control practices and inadequate oversight contributed to the outbreak.