QuickLinks -- Click here to rapidly navigate through this document

SECURITIES AND EXCHANGE COMMISSION
WASHINGTON, DC 20549


FORM 8-K

CURRENT REPORT

Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934

Date of report (Date of earliest event reported): October 13, 2003

Packaging Corporation of America
(Exact name of registrant as specified in its charter)

Delaware   1-15399   36-4277050
(State or other jurisdiction
of incorporation)
  (Commission
File Number)
  (IRS Employer
Identification No.)

1900 West Field Court, Lake Forest, Illinois 60045
(Address of Principal Executive Offices, including Zip Code)

(847) 482-3000
(Registrant's Telephone Number, Including Area Code)





Item 7.    Financial Statements, Pro Forma Financial Information and Exhibits.


Item 12.    Results of Operations and Financial Condition.

        The following information is being furnished under Item 12 of Form 8-K "Results of Operations and Financial Condition."

        On October 13, 2003, we issued a press release announcing third quarter 2003 financial results and providing earnings guidance for the fourth quarter of 2003. The press release is attached as Exhibit 99.1 to this report on Form 8-K and is incorporated herein by reference.

2




SIGNATURES

        Pursuant to the requirements of the Securities Exchange Act of 1934, the registrant has duly caused this report to be signed on its behalf by the undersigned hereunto duly authorized.

    PACKAGING CORPORATION OF AMERICA
      (Registrant)

 

 

By:

/s/  
PAUL T. STECKO      
Chairman and Chief Executive Officer
(Authorized Officer)

 

 

By:

/s/  
RICHARD B. WEST      
Senior Vice President, Chief Financial
Officer, and Corporate Secretary
(Principal Financial Officer)

Date: October 13, 2003

 

 

 
       

3




QuickLinks

SIGNATURES