EXHIBIT 3.1

Cert. No.: 562659

Companies Act 2014

A PUBLIC COMPANY LIMITED BY SHARES

CONSTITUTION

STRONGBRIDGE BIOPHARMA PUBLIC LIMITED COMPANY

MEMORANDUM OF ASSOCIATION

(As amended by special resolution on 6 August 2015, effective 7 August 2015)

The name of the Company is Strongbridge Biopharma public limited company.

The Company is to be a public limited company for the purposes of Part 17 of the Companies Act 2014.

The objects for which the Company is established are:

To carry on the business of a pharmaceuticals company, and to research, develop, design, manufacture, produce, supply, buy, sell, distribute, import, export, provide, promote and otherwise deal in pharmaceuticals, active pharmaceutical ingredients and dosage pharmaceuticals and other devices or products of a pharmaceutical or healthcare character and to hold intellectual property rights and to do all things usually dealt in by persons carrying on the above mentioned businesses or any of them or likely to be required in connection with any of the said businesses.

To carry on the business of a holding company and to co-ordinate the administration, finances and activities of any subsidiary companies or associated companies, to do all lawful acts and things whatever that are necessary or convenient in carrying on the business of such a holding company and in particular to carry on the business of a management services company, to act as managers and to direct or coordinate the management of other companies or of the business, property and estates of any company or person and to undertake and carry out all such services in connection therewith as may be deemed expedient by the Company’s board of directors and to exercise its powers as a shareholder of other companies.

To acquire shares, stocks, debentures, debenture stock, bonds, obligations and securities by original subscription, tender, purchase, exchange or otherwise and to subscribe for the same either conditionally or otherwise, and to guarantee the subscription thereof and to exercise and enforce all rights and powers conferred by or incidental to the ownership thereof.

To facilitate and encourage the creation, issue or conversion of and to offer for public subscription debentures, debenture stocks, bonds, obligations, shares, stocks, and securities and to act as trustees in connection with any such securities and to take part in the conversion of business concerns and undertakings into companies.

To purchase or by any other means acquire any freehold, leasehold or other property and in particular lands, tenements and hereditaments of any tenure, whether subject or not to any

charges or incumbrances, for any estate or interest whatever, and any rights, privileges or easements over or in respect of any property, and any buildings, factories, mills, works, wharves, roads, machinery, engines, plant, live and dead stock, barges, vessels or things, and any real or personal property or rights whatsoever which may be necessary for, or may conveniently be used with, or may enhance the value or property of the Company, and to hold or to sell, let, alienate, mortgage, charge or otherwise deal with all or any such freehold, leasehold, or other property, lands, tenements or hereditaments, rights, privileges or easements.

To sell or otherwise dispose of any of the property or investments of the Company.

To establish and contribute to any scheme for the purchase of shares in the Company to be held for the benefit of the Company’s employees and to lend or otherwise provide money to such schemes or the Company’s employees or the employees of any of its subsidiary or associated companies to enable them to purchase shares of the Company.

To grant, convey, transfer or otherwise dispose of any property or asset of the Company of whatever nature or tenure for such price, consideration, sum or other return whether equal to or less than the market value thereof and whether by way of gift or otherwise as the Directors shall deem fit and to grant any fee, farm grant or lease or to enter into any agreement for letting or hire of any such property or asset for a rent or return equal to or less than the market or rack rent therefor or at no rent and subject to or free from covenants and restrictions as the Directors shall deem appropriate.

To acquire and undertake the whole or any part of the business, good-will and assets of any person, firm or company carrying on or proposing to carry on any of the businesses which this Company is authorised to carry on, and as part of the consideration for such acquisition to undertake all or any of the liabilities of such person, firm or company, or to acquire an interest in, amalgamate with, or enter into any arrangement for sharing profits, or for co-operation, or for limiting competition or for mutual assistance with any such person, firm or company and to give or accept by way of consideration for any of the acts or things aforesaid or property acquired, any shares, debentures, debenture stock or securities that may be agreed upon, and to hold and retain or sell, mortgage or deal with any shares, debentures, debenture stock or securities so received.

To apply for, register, purchase, lease, hold, use, control, licence or otherwise acquire any patents, brevets d’invention, copyrights, trademarks, licences, concessions and the like conferring any exclusive or non-exclusive or limited rights to use or any secret or other information as to any invention which may seem capable of being used for any of the purposes of the Company or the acquisition of which may seem calculated directly or indirectly to benefit the Company, and to use, exercise, develop or grant licences in respect of or otherwise turn to account the property, rights or information so acquired.

To enter into partnership or into any arrangement for sharing profits, union of interests, co-operation, joint venture, reciprocal concession or otherwise with any person or company carrying on or engaged in or about to carry on or engage in any business or transaction which the Company is authorised to carry on or engage in or any business or transaction capable of being conducted so as directly to benefit this Company.

To invest and deal with the moneys of the Company not immediately required upon such securities and in such manner as may from time to time be determined.

To lend money to and guarantee the performance of the contracts or obligations of any company, firm or person, and the repayment of the capital and principal of, and dividends, interest or premiums payable on, any stock, shares and securities of any company, whether having objects similar to those of this Company or not, and to give all kinds of indemnities.

To engage in currency exchange and interest rate transactions including, but not limited to, dealings in foreign currency, spot and forward rate exchange contracts, futures, options, forward rate agreements, swaps, caps, floors, collars and any other foreign exchange or interest rate hedging arrangements and such other instruments as are similar to, or derived from, any of the foregoing whether for the purpose of making a profit or avoiding a loss or managing a currency or interest rate exposure or any other exposure or for any other purpose.

To guarantee, support or secure, whether by personal covenant or by mortgaging or charging all or any part of the undertaking, property and assets (both present and future) and uncalled capital of the Company, or by both such methods, the performance of the obligations of, and the repayment or payment of the principal amounts of and premiums, interest and dividends on any securities of, any person, firm or company including (without prejudice to the generality of the foregoing) any company which is for the time being the Company’s holding company as defined by the Companies Act 2014 or a subsidiary as therein defined of any such holding company or otherwise associated with the Company in business.

To borrow or secure the payment of money in such manner as the Company shall think fit, and in particular by the issue of debentures, debenture stocks, bonds, obligations and securities of all kinds, either perpetual or terminable and either redeemable or otherwise and to secure the repayment of any money borrowed, raised or owing by trust deed, mortgage, charge, or lien upon the whole or any part of the Company’s property or assets (whether present or future) including its uncalled capital, and also by a similar trust deed, mortgage, charge or lien to secure and guarantee the performance by the Company of any obligation or liability it may undertake.

To draw, make, accept, endorse, discount, execute, negotiate and issue promissory notes, bills of exchange, bills of lading, warrants, debentures and other negotiable or transferable instruments.

To subscribe for, take, purchase or otherwise acquire and hold shares or other interests in, or securities of any other company having objects altogether or in part similar to those of this Company, or carrying on any business capable of being conducted so as directly or indirectly to benefit this Company.

To hold in trust as trustees or as nominees and to deal with, manage and turn to account, any real or personal property of any kind, and in particular shares, stocks, debentures, securities, policies, book debts, claims and chases in actions, lands, buildings, hereditaments, business concerns and undertakings, mortgages, charges, annuities, patents, licences, and any interest in real or personal property, and any claims against such property or against any person or company.

To constitute any trusts with a view to the issue of preferred and deferred or other special stocks or securities based on or representing any shares, stocks and other assets specifically

appropriated for the purpose of any such trust and to settle and regulate and if thought fit to undertake and execute any such trusts and to issue, dispose of or hold any such preferred, deferred or other special stocks or securities.

To give any guarantee in relation to the payment of any debentures, debenture stock, bonds, obligations or securities and to guarantee the payment of interest thereon or of dividends on any stocks or shares of any company.

To construct, erect and maintain buildings, houses, flats, shops and all other works, erections, and things of any description whatsoever either upon the lands acquired by the Company or upon other lands and to hold, retain as investments or to sell, let, alienate, mortgage, charge or deal with all or any of the same and generally to alter, develop and improve the lands and other property of the Company.

To provide for the welfare of persons in the employment of or holding office under or formerly in the employment of or holding office under the Company including Directors and ex-Directors of the Company or any of its subsidiary or associated companies and the spouses, civil partners, widows, widowers, families, dependants or connections of such persons by grants of money, pensions or other payments and by forming and contributing to pension, provident or benefit funds or profit sharing or co-partnership schemes for the benefit of such persons and to form, subscribe to or otherwise aid charitable, benevolent, religious, scientific, national or other institutions, exhibitions or objects which shall have any moral or other claims to support or aid by the Company by reason of the locality of its operation or otherwise.

To remunerate by cash payments or allotment of shares or securities of the Company credited as fully paid up or otherwise any person or company for services rendered or to be rendered to the Company whether in the conduct or management of its business, or in placing or assisting to place or guaranteeing the placing of any of the shares of the Company’s capital, or any debentures or other securities of the Company or in or about the formation or promotion of the Company.

To enter into and carry into effect any arrangement for joint working in business or for sharing of profits or for amalgamation with any other company or association or any partnership or person carrying on any business within the objects of the Company.

To distribute in specie or otherwise as may be resolved, any assets of the Company among its members and in particular the shares, debentures or other securities of any other company belonging to this Company or of which this Company may have the power of disposing.

To vest any real or personal property, rights or interest acquired or belonging to the Company in any person or company on behalf of or for the benefit of the Company, and with or without any declared trust in favour of the Company.

To transact or carry on any business which may seem to be capable of being conveniently carried on in connection with any of these objects or calculated directly or indirectly to enhance the value of or facilitate the realisation of or render profitable any of the Company’s property or rights.

To accept stock or shares in or debentures, mortgages or securities of any other company in payment or part payment for any services rendered or for any sale made to or debt owing from any such company, whether such shares shall be wholly or partly paid up.

To pay all costs, charges and expenses incurred or sustained in or about the promotion and establishment of the Company or which the Company shall consider to be preliminary thereto and to issue shares as fully or in part paid up, and to pay out of the funds of the Company all brokerage and charges incidental thereto.

To procure the Company to be registered or recognised in any part of the world.

To do all or any of the matters hereby authorised in any part of the world or in conjunction with or as trustee or agent for any other company or person or by or through any factors, trustees or agents.

To make gifts, pay gratuities or grant bonuses to current and former Directors (including substitute directors), officers or employees of the Company or to make gifts or pay gratuities to any person on their behalf or to charitable organisations, trusts or other bodies corporate nominated by any such person.

To do all such other things that the Company may consider incidental or conducive to the attainment of the above objects or as are usually carried on in connection therewith.

To carry on any business which the Company may lawfully engage in and to do all such things incidental or conducive to the business of the Company.

To make or receive gifts by way of capital contribution or otherwise.

The objects set forth in any sub-clause of this clause shall be regarded as independent objects and shall not, except where the context expressly so requires, be in any way limited or restricted by reference to or inference from the terms of any other sub-clause, or by the name of the Company. None of such sub-clauses or the objects therein specified or the powers thereby conferred shall be deemed subsidiary or auxiliary merely to the objects mentioned in the first sub-clause of this clause, but the Company shall have full power to exercise all or any of the powers conferred by any part of this clause in any part of the world notwithstanding that the business, property or acts proposed to be transacted, acquired or performed do not fall within the objects of the first sub-clause of this clause.

NOTE: It is hereby declared that the word “company” in this clause, except where used in reference to this Company shall be deemed to include any partnership or other body of persons whether incorporated or not incorporated and whether domiciled in Ireland or elsewhere and the intention is that the objects specified in each paragraph of this clause shall except where otherwise expressed in such paragraph be in no way limited or restricted by reference to or inference from the terms of any other paragraph.

The liability of the members is limited.

The share capital of the Company is €40,000 and US$7,000,000 divided into 40,000 deferred ordinary shares of €1.00 each, 600,000,000 ordinary shares of US$0.01 each and 100,000,000 preferred shares of US$0.01 each.

The shares forming the capital, increased or reduced, may be increased or reduced and be divided into such classes and issued with any special rights, privileges and conditions or with such qualifications as regards preference, dividend, capital, voting or other special incidents, and be held upon such terms as may be attached thereto or as may from time to time be provided by the original or any substituted or amended articles of association and regulations of the Company for the time being, but so that where shares are issued with any preferential or special rights attached thereto such rights shall not be alterable otherwise than pursuant to the provisions of the Company’s articles of association for the time being.