MHH may refer to:

• Marsh Harbour Airport's IATA code
• {{lang|de|Medizinische Hochschule Hannover}} or Hannover Medical School

• Diazolidinylurea
• Diazomata
• Diazonium
• Diazonium compounds
• Diazonium Salt
• Diazopam
• Diazo prints
• Diazotation
• Diazo-thioketone coupling
• Diazotization
• Diazpam
• Diaz (rapper)
• .DIB
• Dib
• Diba
• Dibagat
• DIBAH
• Dibai
• Dibaj
• Dibal
• Di Ballo (overture)
• Dibamus alfredi
• Dibamus nicobaricum
• Dibango
• Dibang Valley