FactSentinel

Verdict: False, with an important caveat.

The claim says "most millionaires inherited their wealth." Survey-based evidence does not support that broad statement. Large consumer-finance surveys and millionaire studies generally find that most people with seven-figure net worth did not receive their entire fortune as an inheritance. Many built wealth through income, business ownership, home equity, retirement accounts, investing, or a combination of those factors.

That does not mean inheritance is irrelevant. Family background, education, housing help, gifts, and inherited assets can strongly affect who has the opportunity to build wealth. Inheritance also matters more at the very top of the wealth distribution than it does for many ordinary millionaires whose net worth is tied up in a home and retirement savings.

The correct reading is narrower: most millionaires are not simple heirs, but inherited advantage still matters and should not be ignored in a serious discussion of wealth.

Sources reviewed:
Ramsey Solutions National Study of Millionaires: https://www.ramseysolutions.com/retirement/the-national-study-of-millionaires-research
Federal Reserve Survey of Consumer Finances: https://www.federalreserve.gov/econres/scfindex.htm
National Bureau of Economic Research working papers on wealth and inheritance: https://www.nber.org/