William F. Buckley Jr., the author and commentator, and 10 other defendants were accused yesterday by the Securities and Exchange Commission of defrauding the shareholders of a publicly owned corporation controlled by Buckley.

In a major financial settlement filed with the suit, Buckley agreed to return some $1.4 million in stock and cash to the shareholders of Starr Broadcasting Group Inc. Other defendants must contribute another $360,000.

The civil suit, filed by the SEC in U.S. District Court here, accused the defendants of making "false and misleading" statements to both the agency and its shareholders.

The court permanently enjoined the defendants from "obtaining money or property by means of untrue statements...."

Buckley, who resigned as chairman of Starr Broadcasting in August 1978, still owns 20 percent of the stock. A proposal to merge the company into Shamrock Broadcasting, a privately owned company, awaits approval by stockholders and the Federal Communications Commission.

In settling the suit, Buckley and the others neither admitted nor denied the SEC allegations.

Buckley issued a press release yesterday terday saying: "I have never while a director of Starr intentionally misled anyone."

Among the numerous changes in the detailed SEC complaint is that Buckley used his magazine, National Review, as a secret conduit for funds, diverted from the publicly owned corporation, to avoid personal bankruptcy.

The SEC suit alleges that in 1971 Buckley and three executives at Starr Broadcasting formed a private investment partnership called SITCO.

The other partners, all defendants in the SEC suit, were Peter Starr, president of Starr Broadcasting until he was fired in 1976; his brother Michael, the former executive vice president of Starr Broadcasting; and the company's former counsel, Gordon Ryan.

Generally, the SEC suit alleges that the four partners, by a series of complicated and sometimes illegal financial transactions, invested some $7.5 million in an office building in Coral Gables, Fla., and 16 outdoor theaters in Texas.

The Starrs and Ryan, who did not have Buckley's personal financial resources, regularly used Starr Broadcasting funds, interest-free, to finance their stake in the partnership, the SEC said.

By 1974, however, all of the investments had soured and each of the four SITCO partners faced imminent bankruptcy, the SEC said. That summer, with SITCO's debt at $8 million and interest expenses exceeding $100,000 a month, the SEC alleges that Buckley came up with a plan to sell the losing personal investment to the publicly owned Starr Broadcasting.

The SEC quotes a "most confidential memorandum," written by Buckley and dated Oct. 5, 1974, as saying that unless his complex bail-out plan worked, "there are no alternatives that for WFB (Buckley), the two Starrs and Ryan to go into bankrupty."

At the time, Starr Broadcasting had grown from a modest one-raido-station operation, owned by Buckley, in the early 1960s to a communications conglomerate, mainly through the efforts of Peter Starr.

Based in Westport, Conn., Starr Broadcasting in 1974 owned 3 network-affiliated TV stations, 5 radio stations and 6 AM stations. It owned Arlhus Publishing Corp., which operates the Conservative Book Club, and another company that markets recording tape, phonograph records and guitar accessories.

According to the suit, Buckley's 1974 "most confidential" memo proposed "a considerable expansion of (Starr Broadcasting) into the real estate investment field, beginning with SITCO's position..."

The SEC suit names as defendants the members of the board of directors of Starr Broadcasting who agreed to take over the ailing partnership owned by their fellow board members. They are Maurice McGill, Robert H. Smith Jr., Mark Hannah Jr., Norman Francis and Glenn Burrus. Only Hannah is still a Starr Broadcasting director.

The SEC says that Burrus not only was a Starr Broadcasting board member. but also was an executive at Columbia Union National Bank & Trust Co. in Kansas City, Mo. Burrus had arranged loans of $850,000 at his bank for Buckley and his partners which could have been lost if Sitco went bankrupt. The bank, which is named as a defendent by the SEC, also had loans to Starr Proadcasting.

Columbia Union agreed in the future not to allow officers to serve on the boards of companies to which it lends money.

Burrus, who Buckley in his press release yesterday describes as a "disinterested" board member, was chairman of the committee at Starr Broadcasting that voted in August 1974 to take an option on acquiring SITCO. It also voted to pay SITCO $400,000 to keep it afloat while the option was under consideration.

Prepartory to the deal with Starr Broadcasting, appraisers put inflated values on the partnership's assets. Apparently the SEC said the Coral Gables building sold for $300,000 under its appraisal. And a national accounting firm decreased the appraised value of SITCO's movie theaters by $3.3 million. according to the SEC.

Even with the $400,000 from Starr Broadcasting, SITCO was hardpressed to serve its immense debt.

According to the SEC, Buckley arranged in October 1974 for Ryan, who was Starr Broadcasting's general counsel, to issue a check for $30,000 to National Review magazine. The payment purportedly was for "services performed by (National Review) in connection with a challenge to the renewal of Starr Broadcasting's license to operate station WNCN-FM in New York City," the SEC said.

But then National Review, a private Buckley holding, issued its own $30,000 check to SITCO, "which used the funds to meet an overdue payment," the SEC said.

On Oct. 18, 1974, Burrus, acting for the Starr Broadcasting board. signed an agreement for the company to take over the debts and assets of the SITCO partnership.

In 1976, the former partnership, which had become a wholly owned subsidiary of Starr Broadcasting, called SB Theaters, filed for voluntary bankruptcy reorganization. The parent company has claimed that it lost more than $10 million on the SITCO acquisition.

Among the other allegations in the SEC suit:

Starr Broadcasting sold a valuable TV station to help finance the SITCO acquisition.

SITCO's books were never audited, and details of the acquisition were hidden from stockholders to avoid suits. The last Starr Broadcasting annual meeting was in 1973, a year before the acquisition.