SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

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SCHEDULE TO

Tender Offer Statement under Section 14(d)(1) or 13(e)(1)

of the Securities Exchange Act of 1934

IMPERIAL OIL
LIMITED

(Name of Subject Company (Issuer))

IMPERIAL OIL LIMITED

(Filing Person(s) (Offeror(s))

Common Stock, without par value

(Title of Class of Securities)

453038408

(CUSIP Number of
Class of Securities)

Ian Laing

Vice-President, General Counsel and Corporate Secretary

505 Quarry Park Boulevard S.E.

Calgary, Alberta

Canada T2C 5N1

(800)

567-3776

(Name, address and telephone number of person authorized to receive notices and communications on behalf of the filing person)

Copies to:

Patrick S. Brown

Sullivan & Cromwell LLP

1888 Century Park East

21st Floor

Los Angeles,
California 90067

(310)

712-6603

☐	Check the box if the filing relates solely to preliminary communications made before the commencement of a tender offer.

Check the appropriate boxes below to designate any transactions to which the statement relates:

☐	third-party tender offer subject to Rule 14d-1.

☒	issuer tender offer subject to Rule 13e-4.

☐	going-private transaction subject to Rule 13e-3.

☐	amendment to Schedule 13D under Rule 13d-2.

Check the following box if the filing is a final amendment reporting the results of the tender offer:  ☐

Check the appropriate boxes below to designate any transactions to which the statement relates:

☐	Rule 13e-4(i) (Cross-Border Issuer Tender Offer).

☐	Rule 14d-1(d) (Cross-Border Third-Party Tender Offer).

This Tender Offer Statement on Schedule TO (this “Schedule TO”)
relates to the offer by Imperial Oil Limited, a Canadian corporation (the “Company”), to purchase for cash up to C$1,500,000,000 in value of shares of the Company’s common stock, without par value, net to the seller in cash, without
interest thereon, upon the terms and subject to the conditions set forth in the Offer to Purchase dated November 4, 2022 (the “Offer to Purchase”), together with the accompanying issuer bid circular (the “Issuer Bid
Circular”), and in the related Letter of Transmittal, copies of which are attached as Exhibits (a)(1)(i) and (a)(1)(ii) (which, together with any amendments or supplements thereto, collectively constitute the “Offer”).

This Schedule TO is being filed on behalf of the Company. The information set forth in the Offer to Purchase, the Issuer Bid
Circular and the related Letter of Transmittal is incorporated herein by reference with respect to Items 1 through 9 and 11 of this Schedule TO. The exhibits identified in Item 12 and attached hereto are incorporated herein by reference with respect
to Items 5 and 11 of this Schedule TO.

ITEM 1.

SUMMARY TERM SHEET.

The information set forth in the section of the Offer to Purchase titled “Summary” is incorporated herein by
reference.

ITEM 2.

SUBJECT COMPANY INFORMATION.

(a)

Name and Address

: The name of the issuer is Imperial Oil Limited. The address of the Company’s principal
executive offices is 505 Quarry Park Boulevard S.E., Calgary, AB, Canada T2C 5N1. The Company’s telephone number is (800)

567-3776.

(b)

Securities

: This Schedule TO relates to the Shares of the Company. As of October 31, 2022, there were
604,842,373 issued and outstanding Shares. The information set forth in the section of the Offer to Purchase titled

“The Offer”
is incorporated herein by reference.

(c)

Trading Market and Price

: The information set forth in the section of the
Issuer Bid Circular titled “Price Range of Shares” is incorporated herein by reference.

ITEM 3.

IDENTITY AND BACKGROUND OF FILING PERSON.

(a)

Name and Address

: Imperial Oil Limited. is the filing person and issuer. The information set forth in Item 2(a) is
incorporated herein by reference.

ITEM 4.

TERMS OF THE TRANSACTION.

(a)

Material Terms

: The information set forth in the section of the Offer to Purchase titled “Summary” and in
Section 1 (“The Offer”), Section 2 (“Purchase Price”), Section 3 (“Number of Shares, Proration and Proportionate Tenders”), Section 4 (“Announcement of Results of the Offer”),
Section 5 (“Procedure for Depositing Shares”), Section 6 (“Withdrawal Rights”), Section 7 (“Certain Condition of the Offer”), Section 8 (“Extension and Variation of the Offer”),
Section 9 (“Taking Up and Payment for Deposited Shares”) and Section 11 (“Liens and Dividends”) of the Offer to Purchase and Section 9 (“Interest of Directors and Officers”) Section 13 (“Income
Tax Considerations”) and Section 15 (“Source of Funds”) of the Issuer Bid Circular is incorporated herein by reference.

(b)

Purchases

: The information set forth in the section of the Offer to Purchase titled “Summary” is
incorporated herein by reference. The information set forth in Section 1 (“The Offer”) of the Offer to Purchase and Section 9 (“Interest of Directors and Officers”) and Section 10 (“Arrangements Concerning
Shares”) of the Issuer Bid Circular is incorporated herein by reference.

ITEM 5.

PAST CONTACTS, TRANSACTIONS, NEGOTIATIONS AND AGREEMENTS.

(a)

Agreements Involving the Subject Company’s Securities

: The information set forth in Section 9
(“Interest of Directors and Officers”) of the Issuer Bid Circular is incorporated herein by reference.

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ITEM 6.

PURPOSES OF THE TRANSACTION AND PLANS OR PROPOSALS.

(a)

Purposes

: The information set forth in the section of the Offer to Purchase titled “Summary” and Section
3 (“Purpose and Effect of the Offer”) of the Issuer Bid Circular is incorporated herein by reference.

(b)

Use of the Securities Acquired

: The information set forth in Section 3 (“Purpose and Effect of the Offer”) of the Issuer Bid Circular is incorporated herein by reference.

(c)

Plans

: The information set forth in the section of the Offer to Purchase titled “Summary” and in Section
7 (“Certain Conditions of the Offer”), and in Section 3 (“Purpose and Effects of the Offer”), Section 4 (“Price Range of Shares”), Section 5 (“Dividend Policy”), Section 9 (“Interest
of Directors and Officers”) and Section 11 (“Material Changes in the Affairs of the Company”) of the Issuer Bid Circular is incorporated herein by reference.

ITEM 7.

SOURCE AND AMOUNT OF FUNDS OR OTHER CONSIDERATION.

(a)

Source of Funds

: The information set forth in the section of the Offer to Purchase titled “Summary” and
in Section 15 (“Source of Funds”) of the Issuer Bid Circular is incorporated herein by reference.

(b)

Conditions

: The information set forth in the section of the Offer to Purchase titled “Summary” and in Section 7 (“Certain Conditions of the Offer”) of the Offer to Purchase is incorporated herein by reference.

(d)

Borrowed Funds

: The information set forth in the section of the Offer to Purchase titled “Summary” is
incorporated herein by reference. The information set forth in Section 15 (“Source of Funds”) of the Issuer Bid

Circular is
incorporated herein by reference.

ITEM 8.

INTEREST IN SECURITIES OF THE SUBJECT COMPANY.

(a)

Securities Ownership

: The information set forth in Section 6 (“Previous Purchases of Shares”),
Section 7 (“Previous Sales of Securities”), Section 8 (“Previous Distributions of Shares”), Section 9 (“Interest of Directors and Officers”) and Section 10 (“Arrangements Concerning Shares”) of
the Issuer Bid Circular is incorporated herein by reference.

(b)

Securities Transactions

: The information set
forth in Section 6 (“Previous Purchases of Shares”), Section 7 (“Previous Sales of Securities”), Section 8 (“Previous Distributions of Shares”), Section 9 (“Interest of Directors and
Officers”) and Section 10 (“Arrangements Concerning Shares”) of the Issuer Bid Circular is incorporated herein by reference.

ITEM 9.

PERSONS/ASSETS, RETAINED, EMPLOYED, COMPENSATED OR USED.

(a) The information set forth in the section of the Offer to Purchase titled “Summary” and in Section 17
(“Depositary”) and Section 18 (“Fees and Expenses”) of the Issuer Bid Circular is incorporated herein by reference.

ITEM 10.

FINANCIAL STATEMENTS.

Not applicable.

ITEM 11.

ADDITIONAL INFORMATION.

(a)(1) The information set forth in Section 6 (“Previous Purchases of Shares”), Section 7 (“Previous
Sales of Securities”), Section 8 (“Previous Distributions of Shares”), Section 9 (“Interest of Directors and Officers”) and Section 10 (“Arrangements Concerning Shares”) of the Issuer Bid Circular is
incorporated herein by reference.

(a)(2) The information set forth in Section 14 (“Legal Matters and Regulatory
Approvals”) of the Issuer Bid Circular is incorporated herein by reference.

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(a)(3) Not applicable.

(a)(4) Not applicable.

(a)(5) None.

(c) The information set forth in the Offer to Purchase and the related Letter of Transmittal, copies of which are filed as
Exhibits (a)(l)(i) and (a)(l)(ii) hereto, respectively, as each may be amended or supplemented from time to time, is incorporated herein by reference. The Company will amend this Schedule TO to include documents that the Company may file with the
SEC after the date of the Offer to Purchase pursuant to Sections 13(a), 13(c) or 14 of the Exchange Act and prior to the expiration of the Offer to the extent required by Rule

13e-4(d)(2)

promulgated under the
Exchange Act. The information contained in all of the exhibits referred to in Item 12 below is incorporated herein by reference.

ITEM 12.

EXHIBITS.

4

†	Included in mailing to shareholders.

*	Filed herewith.

ITEM 13.

INFORMATION REQUIRED BY SCHEDULE 13E-3.

Not applicable.

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SIGNATURES

After due inquiry and to the best of my knowledge and belief, I certify that the information set forth in this statement is
true, complete and correct.

Date: November 4, 2022

6

EXHIBIT INDEX

†	Included in mailing to shareholders.

*	Filed herewith.