Northern Tier Energy LP

Lock-Up Agreement

[●], 2012

Goldman, Sachs & Co.

Merrill Lynch, Pierce, Fenner & Smith

Incorporated

Barclays Capital, Inc.

As representatives of the several Underwriters

named in Schedule I hereto,

c/o Goldman, Sachs & Co.

200 West Street

New York, New York 10282-2198

Re:  Northern Tier Energy LP- Lock-Up Agreement

Ladies and Gentlemen:

The undersigned understands that you, as representatives (the “Representatives”), propose to enter into an Underwriting Agreement on behalf of the several Underwriters named in Schedule I to such agreement (collectively, the “Underwriters”), with Northern Tier Energy LP, a Delaware limited partnership (the “Company”), providing for a public offering of common units (the “Units”) representing limited partner interests in the Company pursuant to a Registration Statement on Form S-1 on file with the Securities and Exchange Commission (the “SEC”).

In consideration of the agreement by the Underwriters to offer and sell the Units, and of other good and valuable consideration the receipt and sufficiency of which is hereby acknowledged, the undersigned agrees that, during the period specified in the following paragraph (the “Lock-Up Period”), the undersigned will not offer, sell, contract to sell, pledge, grant any option to purchase, make any short sale or otherwise dispose of any common units of the Company, or any options or warrants to purchase any common units of the Company, or any securities convertible into, exchangeable for or that represent the right to receive common units of the Company, whether now owned or hereinafter acquired, owned directly by the undersigned (including holding as a custodian) or with respect to which the undersigned has beneficial ownership within the rules and regulations of the SEC (collectively the "Undersigned's Units"). The foregoing restriction is expressly agreed to preclude the undersigned from engaging in any hedging or other transaction which is designed to or which reasonably could be expected to lead to or result in a sale or disposition of the Undersigned’s Units even if such Units would be disposed of by someone other than the undersigned. Such prohibited hedging or other transactions would include without limitation any short sale or any purchase, sale or grant of any right (including without limitation any put or call option) with respect to any of the Undersigned’s Units or with respect to any security that includes, relates to, or derives any significant part of its value from such Units.

The initial Lock-Up Period will commence on the date of this Lock-Up Agreement and continue for 180 days after the public offering date set forth on the final prospectus used to sell the Units (the “Public Offering Date”) pursuant to the Underwriting Agreement; provided, however, that if (i) during the last 17 days of the initial Lock-Up Period, the Company releases earnings results or announces material news or a material event or (ii) prior to the expiration of the initial Lock-Up Period, the Company announces that it will release earnings results during the 15-day period following the last day of the initial Lock-Up Period, then in each case the Lock-Up Period will be automatically extended until the expiration of the 18-day period beginning on the date of release of the earnings results or the announcement of the material news or material event, as applicable, unless the Representatives waive, in writing, such extension.

The undersigned hereby acknowledges that the Company has agreed in the Underwriting Agreement to provide written notice of any event that would result in an extension of the Lock-Up Period pursuant to the previous paragraph to the undersigned (in accordance with Section 13 of the Underwriting Agreement) and agrees that any such notice properly delivered will be deemed to have been given to, and received by, the undersigned. The undersigned hereby further agrees that, prior to engaging in any transaction or taking any other action that is subject to the terms of this Lock-Up Agreement during the period from the date of this Lock-Up Agreement to and including the 34th day following the expiration of the initial Lock-Up Period, it will give notice thereof to the Company and will not consummate such transaction or take any such action unless it has received written confirmation from the Company that the Lock-Up Period (as such may have been extended pursuant to the previous paragraph) has expired.

Notwithstanding the foregoing, the undersigned may transfer the Undersigned’s Units (i) as a bona fide gift or gifts, provided that the donee or donees thereof agree to be bound in writing by the restrictions set forth herein, (ii) to any trust, partnership, limited liability company or other entity for the direct or indirect benefit of the undersigned or the immediate family of the undersigned, provided that the trustee of the trust or other transferee agrees to be bound in writing by the restrictions set forth herein, and provided further that any such transfer shall not involve a disposition for value, (iii) as distributions to partners or members of the undersigned (including upon any liquidation and dissolution of the undersigned pursuant to a plan of liquidation approved by the undersigned’s partners or members), provided that the partners or members of the undersigned agree to be bound in writing by the restrictions set forth therein and provided further that no filing under Section 16(a) of the Securities Exchange Act of 1934, as amended (the “Exchange Act”) shall be required or shall be voluntarily made as a result of such transfer or distribution, (iv) to the undersigned’s affiliates or to any investment fund or other entity controlled or managed by the undersigned, provided that such affiliate, investment fund or  other entity controlled or managed by the undersigned agrees to be bound in writing by the restrictions set forth therein and provided further that no filing under Section 16(a) of the Exchange Act shall be required or shall be voluntarily made as a result of such transfer, or (v) with the prior written consent of the Representatives on behalf of the Underwriters. For purposes of this Lock-Up Agreement, “immediate family” shall mean any relationship by blood, marriage or adoption, not more remote than first cousin. In addition, notwithstanding the foregoing, if the undersigned is a corporation, the corporation may transfer the common units of the Company to any wholly-owned subsidiary of such corporation; provided, however, that in any such case, it shall be a condition to the transfer that the transferee execute an agreement stating that the transferee is receiving and holding such common units subject to the provisions of this Agreement and there shall be no further transfer of such common units except in accordance with this Agreement, and provided further that any such transfer shall not involve a disposition for value. The undersigned now has, and, except as contemplated by clause (i), (ii), (iii), (iv) or (v) above, for the duration of this Lock-Up Agreement will have, good and marketable title to the Undersigned’s Units, free and clear of all liens, encumbrances, and claims whatsoever.  The undersigned also agrees and consents to the entry of stop transfer instructions with the Company’s transfer agent and registrar against the transfer of the Undersigned’s Units except in compliance with the foregoing restrictions.

The undersigned understands that the Company and the Underwriters are relying upon this Lock-Up Agreement in proceeding toward consummation of the offering.  The undersigned further understands that this Lock-Up Agreement is irrevocable and shall be binding upon the undersigned’s heirs, legal representatives, successors, and assigns; provided, however, that if for any reason the Underwriting Agreement shall be terminated prior to the Closing Date (as defined in the Underwriting Agreement), the agreement set forth above shall likewise be terminated.

Very truly yours,

________________________________________

Exact Name of Unitholder

________________________________________

Authorized Signature

________________________________________

Title