The Washington Post Co. yesterday reported that its third-quarter profits increased 44 percent to $21.7 million from $15.1 million for the same time period last year.

Earnings per share increased 56 percent to $1.69 from $1.08, largely as a result of the company's repurchase of 1.2 million of its Class B shares.

Revenue for the three months ended Sept. 30 was up 15 percent to $259.4 million from $225 million in the same period a year ago. Revenue grew 6 percent at the newspaper division, 13 percent at Newsweek and 16 percent at the Post-Newsweek television stations.

For the first nine months of 1985, the company's profits increased by 57 percent to $80.7 million from $51.3 million and earnings per share grew 66 percent to $6.06 from $3.64.

Nine-month revenue was $787.3 million, up 12 percent over last year's $700.7 million. For the first nine months, the newspaper division's revenue climbed by 8 percent, Newsweek's revenue rose by 4 percent and revenue from the Post-Newsweek television stations jumped by 15 percent.

For the rest of the year, company officials said the outlook "remains excellent, although fourth-quarter growth will not match that of the third quarter."