Solar absorbers based on optical metamaterials are usually designed and fabricated on a rigid substrate. Due to its rigidness, such solar absorbers are limited to planar surfaces. In this study, we investigate the possibility of a flexible solar absorber with nanoscale metallic slit arrays on a flexible polyethylene terephthalate substrate. It is shown that the solar absorptance can be tuned from 0.1 to 0.6 by changing geometry of metallic slit arrays.