Exhibit 3.1

AMENDMENT NO. 2 TO

AMENDED AND RESTATED BY-LAWS OF

KNOWLES CORPORATION

A Delaware Corporation

Pursuant to a resolution duly adopted by the Board of Directors of Knowles Corporation, a Delaware corporation (the “Corporation”), effective August 1, 2017, Article II, Section 2.16 of the Amended and Restated By-Laws of the Corporation is amended to read in its entirety as follows:

Section 2.16 Nomination of Directors. Only persons who are nominated in accordance with the following procedures shall be eligible for election as directors of the Corporation, except as may be otherwise provided in the Certificate of Incorporation with respect to the right, if any, of holders of preferred stock of the Corporation to nominate and elect a specified number of directors in certain circumstances. Nominations of persons for election to the Board of Directors may be made at any Annual Meeting of Stockholders or at any Special Meeting of Stockholders called for the purpose of electing directors (i) by or at the direction of the Board of Directors (or any duly authorized committee thereof) or (ii) by any stockholder of the Corporation (a) who is a stockholder of record on the date of the giving of the notice provided for in this Section 2.16 and on the record date for the determination of stockholders entitled to notice of and to vote at such Annual Meeting or Special Meeting, (b) who is entitled to vote at such Annual Meeting or Special Meeting and (c) who complies with the notice procedures set forth in this Section 2.16. Clause (ii) of the preceding sentence shall be the exclusive means for a stockholder to make nominations of persons for election to the Board of Directors.

In addition to any other applicable requirements, for a nomination to be made by a stockholder, such stockholder must have given timely notice thereof in proper written form to the Secretary of the Corporation. To be timely, a stockholder’s notice to the Secretary must be delivered to or be mailed and received at the principal executive offices of the Corporation (a) in the case of an Annual Meeting, not later than the close of business on the ninetieth (90th) day nor earlier than the close of business on the one hundred and twentieth (120th) day prior to the anniversary date of the immediately preceding Annual Meeting of Stockholders; provided, however, that in the event that the Annual Meeting is called for a date that is not within thirty (30) days before or after such anniversary date, or in the case of the Corporation’s first Annual Meeting, notice by the stockholder in order to be timely must be so received not later than the close of business on the tenth (10th) day following the day on which such notice of the date of the Annual Meeting was mailed or such public disclosure of the date of the Annual Meeting was made, whichever first occurs; and (b) in the case of a Special Meeting of Stockholders called for the purpose of electing directors, not later than the close of business on the tenth (10th) day following the day on which notice of the date of the Special Meeting was mailed or public disclosure of the date of the Special Meeting was made, whichever first occurs. In no event shall the adjournment or postponement of an Annual Meeting or a Special Meeting called for the purpose of electing directors, or the public announcement of such an adjournment or postponement, commence a new time period (or extend any time period) for the giving of a stockholder’s notice as described above.

To be in proper written form, a stockholder’s notice to the Secretary must set forth the following information: (a) as to each person whom the stockholder proposes to nominate for election as a director (i) the name, age, business address and residence address of such person, (ii) the principal occupation or employment of such person, (iii) (A) the class or series and number of all shares of stock of the Corporation which are owned, directly or indirectly, beneficially or of record by such person and any affiliates or associates of such person, (B) the name of each nominee holder of shares of all stock of the Corporation owned beneficially but not of record by such person or any affiliates or associates of such person, and the number of such shares of stock of the Corporation held by each such nominee holder, (C) whether and the extent to which any derivative instrument, swap, option, warrant, short interest, hedge or profit interest or other transaction has been entered into by or on behalf of such person, or any affiliates or associates of such person, with respect to stock of the Corporation and (D) whether and the extent to which any other transaction, agreement, arrangement or understanding (including any short position or any borrowing or lending of shares of stock of the Corporation) has been made by or on behalf of such person, or any affiliates or associates of such person, the effect or intent of any of the foregoing being to mitigate loss to, or to manage risk or benefit of stock price changes for, such person, or any affiliates or associates of such person, or to increase or decrease the voting power or pecuniary or economic interest of such person, or any affiliates or associates of such person, with respect to stock of the Corporation; and (iv) any other information relating to such person that would be required to be disclosed in a proxy statement or other filing required to be made in connection with solicitations of proxies for election of directors pursuant to Section 14 of the Exchange Act, and the rules and regulations promulgated thereunder; and (b) as to the stockholder giving the notice, and the beneficial owner, if any, on whose behalf the nomination is being made, (i) the name and record address of the stockholder giving the notice and the name and principal place of business of such beneficial owner; (ii) (A) the class or series and number of all shares of stock of the Corporation which are owned beneficially or of record by such person and any affiliates or associates of such person, (B) the name of each nominee holder of shares of the Corporation owned beneficially but not of record by such person or any affiliates or associates of such person, and the number of shares of stock of the Corporation held by each such nominee holder, (C) whether and the extent to which any derivative instrument, swap, option, warrant, short interest, hedge or profit interest or other transaction has been entered into by or on behalf of such person, or any affiliates or associates of such person, with respect to stock of the Corporation and (D) whether and the extent to which any other transaction, agreement, arrangement or understanding (including any short position or any borrowing or lending of shares of stock of the Corporation) has been made by or on behalf of such person, or any affiliates or associates of such person, the effect or intent of any of the foregoing being to mitigate loss to, or to manage risk or benefit of stock price changes for, such person, or any affiliates or associates of such person, or to increase or decrease the voting power or pecuniary or economic interest of such person, or any affiliates or associates of such person, with respect to stock of the Corporation; (iii) a description of all agreements, arrangements, or understandings (whether written or oral) between or among such person, or any affiliates or associates of such person, and any proposed nominee or any other person or persons (including their names) pursuant to which the nomination(s) are being made by such person, and any material interest of such person, or any affiliates or associates of such person, in such nomination, including any anticipated benefit therefrom to such person, or any affiliates or associates of such person; (iv) a representation (a) that the stockholder giving notice is a holder of record of stock of the

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Corporation entitled to vote at the Annual Meeting or Special Meeting and intends to appear in person or by proxy at the Annual Meeting or Special Meeting to nominate the persons named in its notice and (b) whether the stockholder (and any beneficial owners on whose behalf the nomination is made) intends to continue to hold the shares through the date of the Annual Meeting or Special Meeting; (v) a representation whether the stockholder or any of the beneficial owners intends or is part of a group which intends (a) to deliver a proxy statement and/or form of proxy to holders of at least the percentage of the Corporation’s outstanding capital stock which, together with the holdings of such stockholder and all such beneficial owners, is sufficient to elect the nominee, and/or (b) otherwise to solicit proxies from stockholders in support of such nomination; and (vi) any other information relating to such person that would be required to be disclosed in a proxy statement or other filings required to be made in connection with the solicitation of proxies for election of directors pursuant to Section 14 of the Exchange Act and the rules and regulations promulgated thereunder. Such notice must be accompanied by a written consent of each proposed nominee to being named as a nominee and stating such nominee’s intention, if elected, to serve the full term of the class of directors for which such nominee is standing for election. The Corporation may require any proposed nominee to furnish such other information as the Corporation may reasonably require to determine the eligibility of such proposed nominee to serve as a director of the Corporation.

A stockholder providing notice of any nomination proposed to be made at an Annual Meeting or Special Meeting shall further update and supplement such notice, if necessary, so that the information provided or required to be provided in such notice pursuant to this Section 2.16 shall be true and correct as of the record date for determining the stockholders entitled to receive notice of the Annual Meeting or Special Meeting, and such update and supplement shall be delivered to or be mailed and received by the Secretary at the principal executive offices of the Corporation not later than five (5) business days after the record date for determining the stockholders entitled to receive notice of such Annual Meeting or Special Meeting.

No person shall be eligible for election as a director of the Corporation unless nominated in accordance with the procedures set forth in this Section 2.16. If the chair of the meeting determines that a nomination was not made in accordance with the foregoing procedures, the chair shall declare to the meeting that the nomination was defective, and such defective nomination shall be disregarded.

Notwithstanding the foregoing provisions of this Section 2.16, unless otherwise required by law or expressly waived in writing by the Corporation, if the stockholder (or a qualified representative of the stockholder) does not appear at the Annual Meeting or Special Meeting to present such nomination, such nomination shall be disregarded, notwithstanding that proxies in respect of such vote may have been received by the Corporation. For purposes of this Section 2.16, to be considered a qualified representative of the stockholder, a person must be a duly authorized officer, manager or partner of such stockholder or must be authorized by a writing executed by such stockholder or an electronic transmission delivered by such stockholder to act for such stockholder as proxy at the Annual Meeting or Special Meeting and such person must produce such writing or electronic transmission, or a reliable reproduction of the writing or electronic transmission, at the Annual Meeting or Special Meeting.

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