In this article, an adaptive filtering approach to compensate for instrument dynamics effect on nanoscale broadband material viscoelasticity measurements is proposed. Although a large frequency range of measurement (i.e., broadband) is desirable in mechanical property characterization of materials, the measurement frequency range is, in general, limited by the dynamics of the measurement instrument. Such a limit arises because the instrument dynamics can be convoluted with the mechanical response of the material in the measured data, particularly when the excitation force profile consists of multiple frequencies and becomes fast. The contribution of this article is the use of adaptive filtering approach to eliminate the instrument dynamics effect in nanoscale broadband viscoelasticity measurement using atomic force microscope (AFM). The proposed approach is illustrated by implementing it to compensate for the dynamic effects in the broadband viscoelasticity measurement of a polydimethylsiloxane (PDMS) sample using AFM.