Exhibit 99.1

Monolithic Power Systems, Inc.

79 Great Oaks Boulevard

San Jose, CA 95119 USA

T: 408-826-0600, F: 408-826-0601

www.monolithicpower.com

Monolithic Power Systems Announces Results for the Second Quarter Ended June 30, 2018

SAN JOSE, California, July 25, 2018--Monolithic Power Systems, Inc. (MPS) (Nasdaq: MPWR), a leading company in high performance analog solutions, today announced financial results for the quarter ended June 30, 2018.

   The results for the quarter ended June 30, 2018 are as follows:

   The results for the six months ended June 30, 2018 are as follows:

The following is a summary of revenue by end market for the periods indicated (in thousands):

The following is a summary of revenue by product family for the periods indicated (in thousands):

“We are continuing to execute our long-term business strategy, which we believe will maximize long-term shareholder value," said Michael Hsing, CEO and founder of MPS.

Business Outlook

The following are MPS’ financial targets for the third quarter ending September 30, 2018:

(1) Non-GAAP net income, non-GAAP earnings per share, non-GAAP gross margin, non-GAAP R&D and SG&A expenses, non-GAAP operating expenses, non-GAAP interest and other income, net, non-GAAP operating income and non-GAAP income before taxes differ from net income, earnings per share, gross margin, R&D and SG&A expenses, operating expenses, interest and other income, net, operating income and income before taxes determined in accordance with Generally Accepted Accounting Principles in the United States (GAAP). Non-GAAP net income and non-GAAP earnings per share exclude the effect of stock-based compensation expense, amortization of acquisition-related intangible assets, deferred compensation plan income/expense and related tax effects. Non-GAAP gross margin excludes the effect of stock-based compensation expense and amortization of acquisition-related intangible assets. Non-GAAP operating expenses exclude the effect of stock-based compensation expense and deferred compensation plan income/expense. Non-GAAP interest and other income, net excludes the effect of deferred compensation plan income/expense. Non-GAAP operating income excludes the effect of stock-based compensation expense, amortization of acquisition-related intangible assets and deferred compensation plan income/expense. Non-GAAP income before taxes excludes the effect of stock-based compensation expense, amortization of acquisition-related intangible assets and deferred compensation plan income/expense. Projected non-GAAP gross margin excludes the effect of stock-based compensation expense and amortization of acquisition-related intangible assets. Projected non-GAAP R&D and SG&A expenses exclude the effect of stock-based compensation expense. These non-GAAP financial measures are not prepared in accordance with GAAP and should not be considered as a substitute for, or superior to, measures of financial performance prepared in accordance with GAAP. A schedule reconciling non-GAAP financial measures is included at the end of this press release. MPS utilizes both GAAP and non-GAAP financial measures to assess what it believes to be its core operating performance and to evaluate and manage its internal business and assist in making financial operating decisions. MPS believes that the inclusion of non-GAAP financial measures, together with GAAP measures, provides investors with an alternative presentation useful to investors' understanding of MPS' core operating results and trends. Additionally, MPS believes that the inclusion of non-GAAP measures, together with GAAP measures, provides investors with an additional dimension of comparability to similar companies. However, investors should be aware that non-GAAP financial measures utilized by other companies are not likely to be comparable in most cases to the non-GAAP financial measures used by MPS.

Conference Call

MPS plans to conduct an investor teleconference covering its financial results at 2:00 p.m. PT / 5:00 p.m. ET, July 25, 2018. To access the conference call and the following replay of the conference call, go to http://ir.monolithicpower.com and click on the webcast link. From this site, you can listen to the teleconference, assuming that your computer system is configured properly. In addition to the webcast replay, which will be archived for all investors for one year on the MPS website, a phone replay will be available for seven days after the live call at (404) 537-3406, code number 4579634. This press release and any other information related to the call will also be posted on the website.

Safe Harbor Statement

This press release contains, and statements that will be made during the accompanying teleconference will contain, forward-looking statements, as that term is defined in the Private Securities Litigation Reform Act of 1995, including, among other things, (i) projected revenues, GAAP and non-GAAP gross margin, GAAP and non-GAAP R&D and SG&A expenses, stock-based compensation expenses, amortization of acquisition-related intangible assets, interest and other income, and diluted shares outstanding, (ii) our outlook for the long-term prospects of the company, including our performance against our business plan, revenue growth in certain of our market segments, our continued investment into R&D, expected revenue growth, customers' acceptance of our new product offerings, the prospects of our new product development, and our expectations regarding market and industry segment trends and prospects, (iii) our ability to penetrate new markets and expand our market share, (iv) the seasonality of our business, (v) our ability to reduce our expenses, (vi) the impact of the 2017 Tax Act on our tax rate and provision; and (vii) statements of the assumptions underlying or relating to any statement described in (i), (ii), (iii), (iv), (v), or (vi). These forward-looking statements are not historical facts or guarantees of future performance or events, are based on current expectations, estimates, beliefs, assumptions, goals, and objectives, and involve significant known and unknown risks, uncertainties and other factors that may cause actual results to be materially different from the results expressed by these statements. Readers of this press release and listeners to the accompanying conference call are cautioned not to place undue reliance on any forward-looking statements, which speak only as of the date hereof. Factors that could cause actual results to differ include, but are not limited to, our ability to attract new customers and retain existing customers; acceptance of, or demand for, MPS' products, in particular the new products launched recently, being different than expected; our ability to efficiently and effectively develop new products and receive a return on our R&D expense investment; competition generally and the increasingly competitive nature of our industry; any market disruptions or interruptions in MPS' schedule of new product development releases; adverse changes in production and testing efficiency of our products; our ability to realize the anticipated benefits of companies and products that we acquire, and our ability to effectively and efficiently integrate these acquired companies and products into our operations; our ability to manage our inventory levels; adverse changes in laws and government regulations, including in foreign countries where MPS has offices or operations; adverse events arising from orders of governmental entities, including such orders that impact our customers, and adopting of new or amended accounting standards; the effect of catastrophic events; adequate supply of our products from our third-party manufacturing partners; the risks, uncertainties and costs of litigation in which we are involved; the outcome of any upcoming trials, hearings, motions and appeals; the adverse impact on MPS' financial performance if its tax and litigation provisions are inadequate; adverse changes or developments in the semiconductor industry generally, which is cyclical in nature; difficulty in predicting or budgeting for future customer demand and channel inventories, expenses and financial contingencies; the ongoing consolidation of companies in the semiconductor industry; and other important risk factors identified in MPS' Securities and Exchange Commission (SEC) filings, including, but not limited to, our annual report on Form 10-K filed with the SEC on March 1, 2018 and our quarterly report on Form 10-Q filed with the SEC on May 8, 2018. The forward-looking statements in this press release and statements made during the accompanying teleconference represent MPS' projections and current expectations, as of the date hereof, not predictions of actual performance. MPS assumes no obligation to update the information in this press release or in the accompanying conference call.

About Monolithic Power Systems

Monolithic Power Systems, Inc. (MPS) provides small, highly energy efficient, easy-to-use power solutions for systems found in industrial applications, telecom infrastructures, cloud computing, automotive, and consumer applications. MPS' mission is to reduce total energy consumption in its customers' systems with green, practical, compact solutions. The company was founded by Michael Hsing in 1997 and is based in the United States. MPS can be contacted through its website at www.monolithicpower.com or its support offices around the world.

Monolithic Power Systems, MPS, and the MPS logo are registered trademarks of Monolithic Power Systems, Inc. in the U.S. and trademarked in certain other countries.

Contact:

Bernie Blegen

Chief Financial Officer

Monolithic Power Systems, Inc.

408-826-0777

investors@monolithicpower.com

Monolithic Power Systems, Inc.

Condensed Consolidated Balance Sheets

(Unaudited, in thousands, except par value)

Monolithic Power Systems, Inc.

Condensed Consolidated Statements of Operations

(Unaudited, in thousands, except per share amounts)