Subperiosteal abscess formation is almost exclusively seen secondary to underlying hematogenous infected osteomyelitis or secondary as a result of a contagious focus. We present an unusual case of a 9-year-old girl with progressive ankle pain due to an isolated subperiosteal abscess of the distal fibula without concomitant osteomyelitis. The subperiosteal abscess was most likely caused by hematogenous spread to the periosteal region of the distal fibula located above the highly vascularized metaphysis. Remarkably, there were no signs of osteomyelitis on either MRI or during surgical inspection. She was successfully treated with debridement and antibiotic therapy. We hypothesize that subperiosteal abscess formation near the metaphysis originates in the periosteal region and not from outward extension from the sinusoidal veins in the intrametaphyseal area to the cortex and subperiosteal region.