The temperature dependent band structure of the pentatelluride ZrTe5 has been examined using the technique of high-resolution angle-resolved photoemission in conjunction with synchrotron radiation. Specifically, the band dispersion along the X-Γ-X high symmetry axis was mapped at 20K (T<Tc) and 170K (T>Tc), where Tc≃160K. One electron band and two hole bands within 0.5eV of the Fermi level have been identified. The dispersion of the bands indicates that they have extremely small electron and hole effective masses. The hole bands were observed to distort and shift in energy upon raising the sample temperature above Tc, indicative of a surface distortion.