INTRODUCTION: In spinal muscular atrophy (SMA), irreversible loss of spinal motor neurons and progressive skeletal muscle atrophy cause continuous weakness and loss of motor function. Treatments that increase levels of survival motor neuron (SMN) protein in motor neurons have greatly improved prognoses for patients, but significant unmet needs remain. Myostatin is a protein secreted by skeletal muscle that acts as a negative regulator of muscle growth. Inhibition of the myostatin signaling pathway may improve motor function in SMA and other neuromuscular diseases. AREAS COVERED: This article reviews the role of muscle in SMA and the potential for treatments that inhibit the myostatin signaling pathway in neuromuscular diseases. Preclinical and clinical trial data are discussed for these muscle-targeted treatments in development for SMA. EXPERT OPINION: SMN-targeted disease-modifying treatments focus on motor neuron survival rather than muscle. Treated individuals nonetheless experience a range of persistent muscle weakness. Treatments that inhibit myostatin signaling represent a potential complementary pathway for direct muscle enhancement. In the evolving SMA treatment landscape, understanding how muscle-targeted treatment can be incorporated into clinical practice will facilitate individualized treatment decisions and identify outcomes that best encapsulate maintenance or improvement of motor function across the phenotypic spectrum of SMA.