A motor mount assembly is provided for coupling a propeller motor to a body of an unmanned aerial vehicle (UAV). The motor mount assembly includes a floating portion and acts to attenuate frequencies of vibration from the propeller motor during operation, which modifies the corresponding noise that is produced and reduces stresses on the various components. The floating portion is surrounded on all sides by isolation portions (e.g., made of elastomers or other materials) that are held within a casing that attaches to the body of the UAV. In one implementation, the motor mount assembly is modular such that one or more of the isolation portions may be replaced with different isolation portions (e.g., having different attenuation properties), depending on the direction and nature of the vibrations from the propeller motor that are to be attenuated for a particular application.