Substrates micropatterned with cell adhesion proteins have been used to investigate how protein density and geometry affect cell behaviors such as cell migration, growth, and differentiation. Existing technologies are limited in that they typically feature protein micropatterns that are static and unable to change while cells are attached. Here we micropatterned shape memory polymer (SMP) substrates that were capable of transitioning from a stretched state to a contracted state to control the width of patterned lines presented to attached cells. We found that micropattern geometry changed as the SMP substrate transitioned to its unstretched shape. Cells attached to dynamic patterns balled up and contracted their nuclei. The results suggest that micropatterned SMP cell culture substrates can be used to study the temporal aspects of cell mechanobiology.