Aspects of the invention provide single stranded oligonucleotides for activating or enhancing expression of hemoglobin genes (HBB, HBD, HBE1, HBG1 or HBG2). Further aspects provide compositions and kits comprising single stranded oligonucleotides for activating or enhancing expression of hemoglobin genes. Methods for modulating expression of hemoglobin genes using the single stranded oligonucleotides are also provided. Further aspects of the invention provide methods for selecting a candidate oligonucleotide for activating or enhancing expression of hemoglobin genes.