Exhibit 5.1

November 9, 2016

Dover Corporation

3005 Highland Parkway

Downers Grove, Illinois 60515

Ladies and Gentlemen:

I am Senior Vice President, General Counsel and Secretary of Dover Corporation, a Delaware corporation (the “Company”), and, as such, am generally familiar with its affairs, records, documents and obligations. I have acted as counsel to the Company in connection with the issuance and sale of €600,000,000 aggregate principal amount of the Company’s 1.250% Notes due 2026 (the “2016 Securities”) pursuant to a Pricing Agreement, dated as of November 2, 2016 (the “Pricing Agreement”), and related Underwriting Agreement, dated as of November 2, 2016 (together with the Pricing Agreement, the “Underwriting Agreement”), among the Company and the several underwriters named in Schedule I to the Pricing Agreement (collectively, the “Underwriters”). The 2016 Securities will be issued pursuant to an indenture, dated as of February 8, 2001 (the “Base Indenture”), entered into between the Company and The Bank of New York Mellon, as Trustee (as successor to Bank One Trust Company, N.A. and J.P. Morgan Trust Company, National Association) (the “Trustee”), as supplemented by a first supplemental indenture, dated as of October 13, 2005 (the “First Supplemental Indenture”), between the Company and the Trustee, a second supplemental indenture, dated as of March 14, 2008 (the “Second Supplemental Indenture”), between the Company and the Trustee, a third supplemental indenture, dated as of February 22, 2011 (the “Third Supplemental Indenture”), between the Company and the Trustee, a fourth supplemental indenture, dated as of December 2, 2013 (the “Fourth Supplemental Indenture”), among the Company, the Trustee and the Bank of New York Mellon, London Branch, as Paying Agent (the “Paying Agent”), a fifth supplemental indenture, dated as of November 3, 2015 (the “Fifth Supplemental Indenture”), between the Company and the Trustee, and a sixth supplemental indenture, dated as of November 9, 2016 (the “Sixth Supplemental Indenture” and the Base Indenture, as supplemented by the First Supplemental Indenture, the Second Supplemental Indenture, the Third Supplemental Indenture, the Fourth Supplemental Indenture, the Fifth Supplemental Indenture and the Sixth Supplemental Indenture, the “Indenture”), among the Company, the Trustee and the Paying Agent.

I have examined the Company’s Registration Statement on Form S-3ASR (File No. 333-194385) filed by the Company with the Securities and Exchange Commission (the “Commission”) under the Securities Act of 1933, as amended (the “Securities Act”), on March 7, 2014 (the “Registration Statement”) and the prospectus, dated March 6, 2014 (the “Base Prospectus”), as supplemented by the preliminary prospectus supplement, dated November 2, 2016 (the “Preliminary Prospectus Supplement”), and the prospectus supplement, dated November 2, 2016 (the “Prospectus Supplement”), the form of Indenture and the originals or certified, photostatic, electronic or facsimile copies of such records and other documents as I have deemed relevant and necessary as the basis for the opinions set forth below. In such examination, I have assumed the legal capacity of all natural persons, the genuineness of all signatures, the authenticity of all documents submitted to me as originals, the conformity to original documents of all documents submitted to me as certified, photostatic, electronic or facsimile copies and the authenticity of the originals of such copies.

Based upon my examination described above, and subject to the assumptions and qualifications stated herein, I am of the opinion that:

The foregoing opinion is limited to the General Corporation Law of the State of Delaware and the laws of the State of New York. The foregoing opinion is also subject to: (a) applicable bankruptcy, reorganization, insolvency, moratorium, fraudulent conveyance and similar laws which relate to or affect creditors’ rights generally, and (b) general principles of equity, including (1) the possible unavailability of specific performance, injunctive relief or any other equitable remedy and (2) concepts of materiality, reasonableness, conscionability, good faith and fair dealing. In addition, I express no opinion with respect to whether acceleration of the 2016 Securities may affect the collectability of any portion of the stated principal amount thereof which might be determined to constitute unearned interest thereon.

I assume for purposes of this opinion that (i) each of the Trustee and the Paying Agent is duly organized, validly existing and in good standing under the laws of its jurisdiction of organization; (ii) each of the Trustee and the Paying Agent is duly qualified to engage in the activities contemplated by the Indenture; (iii) the Indenture will be duly authorized, executed and delivered by the Trustee and the Paying Agent and will constitute a legal, valid and binding obligation of the Trustee and the Paying Agent, enforceable against each of them in accordance with its terms; (iv) the Trustee and the Paying Agent will be in compliance, generally and with respect to acting as Trustee and Paying Agent, respectively, under the Indenture, with all applicable laws and regulations; and (v) each of the Trustee and the Paying Agent will have the requisite legal power and authority to perform their respective obligations under the Indenture.

I hereby consent to the filing of this opinion as an exhibit to the Company’s Current Report on Form 8-K to be filed on or about November 9, 2016, which Form 8-K will be incorporated by reference into the Registration Statement, and the reference to my name therein and in the related Preliminary Prospectus Supplement and Prospectus Supplement under the caption “Legal Matters.” In giving this consent, I do not thereby admit that I am within the category of persons whose consent is required under Section 7 of the Securities Act or the Rules and Regulations of the Commission promulgated thereunder.

Very truly yours,

/s/ Ivonne M. Cabrera

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