Provided herein are substituted pyrazolylpyridine, pyrazolylpyridazine, and pyrazolylpyrimidine derivative compounds and pharmaceutical compositions comprising said compounds. The subject compounds and compositions are useful for inhibition histone demethylase. Furthermore, the subject compounds and compositions are useful for the treatment of cancer, such as prostate cancer, breast cancer, bladder cancer, lung cancer and/or melanoma and the like.