• observation manipulation bell
• Ocean Modeling Branch - former name of current Marine Modeling and Analysis Branch
• Office of Management and Budget
• * United States Office of Management and Budget
• * (many other govts have an office of this name also)
• Offshore Model Basin
• Old Man Bal from Xenogears
• Olympia Master Builders omb.org
• Olympiade Mathématique Belge
• Ontario Municipal Board
• Opportunity Microfinance Bank
• Oregon Marching Band
• Our Miss Brooks
• Oh my Buddha

"OMB" or "Omb" may also appear as an abbreviation for ombudsman.