Cerebral palsy describes a group of disorders of movement and posture that result from disturbances in the developing brain. Although the brain lesion is nonprogressive, the secondary physical symptoms change with time and growth. If left untreated, symptoms may result in the development of physical impairment and impede independent performance of daily tasks. Intramuscular injection of botulinum neurotoxin A is a relatively safe and effective adjunct to upper limb therapy. Botulinum neurotoxin A primarily aims to reduce muscle overactivity, thereby reducing the development of increased muscle stiffness that can lead to permanent changes. With a specific focus on the physiological action of botulinum neurotoxin A, this article describes the secondary symptoms of cerebral palsy and their different contributions. To highlight research directions and future implications for clinical practice, this article also documents the recent scientific evidence for upper limb botulinum neurotoxin A and proposes a preventive clinical model that aims to mitigate the effects of increasing upper limb impairment.