Muhlenbergia minutissima is a species of grass known by the common name Annual muhly. It is native to North America, where it is found throughout the western United States and much of Mexico. It can be found in many habitat types, including disturbed areas. It is an annual bunchgrass growing 30 centimeters tall. The inflorescence is an open, spreading array of hair-thin branches bearing millimeter-long spikelets.