The function of RORB (RAR related orphan receptor B, Ensembl gene identifier ENSG00000198963) is as follows. Nuclear receptor that binds DNA as a monomer to ROR response elements (RORE) containing a single core motif half-site 5'-AGGTCA-3' preceded by a short A-T-rich sequence. Considered to have intrinsic transcriptional activity, have some natural ligands such as all-trans retinoic acid (ATRA) and other retinoids which act as inverse agonists repressing the transcriptional activity. Required for normal postnatal development of rod and cone photoreceptor cells. Modulates rod photoreceptors differentiation at least by inducing the transcription factor NRL-mediated pathway. In cone photoreceptor cells, regulates transcription of OPN1SW. Involved in the regulation of the period length and stability of the circadian rhythm. May control cytoarchitectural patterning of neocortical neurons during development. May act in a dose-dependent manner to regulate barrel formation upon innervation of layer IV neurons by thalamocortical axons. May play a role in the suppression of osteoblastic differentiation through the inhibition of RUNX2 transcriptional activity (By similarity). . Isoform 1 is critical for hindlimb motor control and for the differentiation of amacrine and horizontal cells in the retina. Regulates the expression of PTF1A synergistically with FOXN4 (By similarity). .