Allergic contact dermatitis (ACD) represents a severe health problem with increasing worldwide prevalence. It is a T-cell-mediated inflammatory skin disease caused by chemicals present in the daily or professional environment. NiSO4 and 2,4-dinitrochlorobenzene (DNCB) are 2 chemicals involved in ACD. These contact sensitizers are known to induce an up-regulation of phenotypic markers and cytokine secretion in dendritic cells (DCs; professional APCs), leading to the generation of CD8+ Tc1/Tc17 and CD4+ Th1/Th17 effector T cells. In the present study, using a peptide array approach, we identified protein kinase CK2 as a novel kinase involved in the activation of human monocyte-derived DCs (MoDCs) in response to NiSO4 and DNCB. Inhibition of CK2 activity in MoDCs led to an altered mature phenotype with lower expression of CD54, PDL-1, CD86, and CD40 in response to NiSO4 or DNCB. CK2 activity also regulated proinflammatory cytokine production, such as TNF-α, IL-1β, and IL-23 in MoDCs. Moreover, in a DC/T cell coculture model in an allogeneic setup, CK2 activity in MoDCs played a major role in Th1 polarization in response to NiSO4 and DNCB. CK2 inhibition in MoDCs led to an enhanced Th2 polarization in the absence of contact sensitizer stimulation.