The decision, revealed by Khomeini's son today, was taken by the Guardian Council, a conservative-dominated committee that decides who can run for public office.
Khomeini was among hundreds of candidates ruled out of standing for the assembly, which monitors the work of Iran's supreme leader, Ayatollah Ali Khamenei.
With an eight-year term of office, its 88 members may also be responsible for picking the 76-year-old's eventual successor.
The rejected candidates have until Saturday to appeal.
Following Iran's recent nuclear deal with world powers led by the United States, both elections are seen as crucial to shaping the country's future direction.
Khomeini is the grandson of Ayatollah Ruhollah Khomeini, the leader of the 1979 Islamic revolution that ended the reign of US-backed Shah Mohammad Reza Pahlavi.
The elder Khomeini, a firebrand conservative who railed against pervasive Western influence, died in 1989.
He remains revered - his image present in every public office, on Iranian banknotes and on countless murals in Tehran and other cities.
At 43, Khomeini is significantly younger than most of the current members of Assembly.
But he was not verified as having sufficient religious competence to contest the ballot, his son said on his Instagram account, which has 199,000 followers.
In a post including a picture of his father studying religious texts, Ahmad Khomeini said the Guardian Council verdict came despite "testimony from dozens of religious authorities".
"It became definite last night (yesterday)" that his father had not been classed as "mojtahed", or sufficiently learned in Islam, to take a place on the assembly, he wrote.
But in his post Khomeini's 18-year-old son cast doubt on that being the grounds for his father's exclusion.
"In my opinion the reason for non-verification is clear to everyone, especially given that some others' ijtehad ("knowledge" in Farsi) has been verified without them sitting for the exam," he wrote.
The Assembly of Experts is comprised solely of clerics. A final list of candidates is expected on February 9.
You’ve reached your limit of {{free_limit}} free articles this month.
Subscribe now for unlimited access.
Already subscribed? Log in
Subscribe to read the full story →
Smart Quarterly
₹900
3 Months
₹300/Month
Smart Essential
₹2,700
1 Year
₹225/Month
Super Saver
₹3,900
2 Years
₹162/Month
Renews automatically, cancel anytime
Here’s what’s included in our digital subscription plans
Exclusive premium stories online
Over 30 premium stories daily, handpicked by our editors


Complimentary Access to The New York Times
News, Games, Cooking, Audio, Wirecutter & The Athletic
Business Standard Epaper
Digital replica of our daily newspaper — with options to read, save, and share


Curated Newsletters
Insights on markets, finance, politics, tech, and more delivered to your inbox
Market Analysis & Investment Insights
In-depth market analysis & insights with access to The Smart Investor


Archives
Repository of articles and publications dating back to 1997
Ad-free Reading
Uninterrupted reading experience with no advertisements


Seamless Access Across All Devices
Access Business Standard across devices — mobile, tablet, or PC, via web or app
