Exhibit 99.1

FOR IMMEDIATE RELEASE

MOBILE MINI REPORTS Q2’15 RESULTS AND ANNOUNCES QUARTERLY DIVIDEND

Phoenix, AZ – July 23, 2015 – Mobile Mini, Inc. (NASDAQ GS: MINI) (the “Company” or “Mobile Mini”), the world’s leading supplier of portable storage solutions, and a leading provider of specialty containment solutions in the United States, today reported actual and adjusted financial results for the quarter ended June 30, 2015. Total revenues were $130.3 million and rental revenues were $120.2 million, up from $106.5 million and $98.0 million, respectively, for the same period last year.

The Company recorded second quarter net income of $9.4 million, or $0.21 per diluted share. The Company had net income of $9.3 million, or $0.20 per diluted share, respectively, for the second quarter of 2014. On an adjusted basis, second quarter net income was $13.0 million, or $0.28 per diluted share, compared to adjusted net income of $10.8 million, or $0.23 per diluted share, for the second quarter of 2014. Adjusted EBITDA was $46.3 million and adjusted EBITDA margin was 35.9% for the second quarter of 2015.

Total revenues and rental revenues for the portable storage business for the current quarter were $103.0 million and $95.0 million, respectively. Total revenues and rental revenues for the recently acquired specialty containment business were $27.3 million and $25.2 million, respectively.

Dividend

The Company’s Board of Directors declared a cash dividend of 18.7 cents per share which will be paid on September 2, 2015 to shareholders of record on August 19, 2015.

Second Quarter 2015 Highlights

CEO Comments

Erik Olsson, Mobile Mini’s President and Chief Executive Officer, remarked, “I’m very pleased with the performance and development of our business in the quarter. Within our North American portable storage business, our recently realigned sales force and operational teams achieved the highest monthly activations in the Company’s history in June, with core activations up 20% from June 2014. As a result, within our portable storage business we grew fleet on rent at June 30, 2015 more than 3% company-wide since the end of the first quarter and 2% year-over-year. Impressive internal sales productivity increases of 28% compared to the prior-year quarter drove the second quarter traction in activations. This momentum has continued into the first few weeks of July, with year-over-year activation increases in excess of 13%, resulting in the Company’s highest ever level of core units on rent.”

Mr. Olsson continued, “We have achieved success with our premium pricing strategy, as reflected in our 5.1% year-over-year rate increase this quarter. To achieve both rate and volume growth we are focused on continued development of our sales force and are actively recruiting representatives with a near-term goal of increasing the internal salesforce approximately 10%, or 20 employees. Our specialty containment business continued to do very well in the downstream market on a year over year basis, while facing continuing headwinds in the upstream market. As expected, the divestiture of our wood mobile office business is resulting in some short-term margin pressure as we incur additional costs and distraction in our field operations.”

Conference Call

Mobile Mini will host a conference call today, Thursday, July 23, 2015 at 12 noon ET to review these results. To listen to the call live, dial (201) 493-6739 and ask for the Mobile Mini Conference Call or go to www.mobilemini.com and click on the Investors section. Additionally, a slide presentation that will accompany the call will be posted at www.mobilemini.com on the Investors section and will be available in advance and after the call. Please go to the website 15 minutes early to download and install any necessary audio software. If you are unable to listen live, a replay of the call can be accessed for approximately 14 days after the call at Mobile Mini’s website.

About Mobile Mini, Inc.

Mobile Mini, Inc. is the world’s leading provider of portable storage solutions through its total rental fleet of approximately 204,200 portable storage containers and office units with 134 locations in the U.S., United Kingdom, and Canada. Through its wholly-owned subsidiary, Evergreen Tank Solutions, Mobile Mini is also a leading provider of specialty containment solutions in the U.S., with a rental fleet of approximately 11,100 units and 23 locations. Mobile Mini is included on the Russell 2000^® and 3000^® Indexes and the S&P Small Cap Index.

Forward-Looking Statements

This news release contains forward-looking statements, including, but not limited to, our expectations regarding our ability to execute our strategic plan, growth increased revenue, increased operational flexibility and efficiency, financial performance, margin expansion, ability to enter new markets, free cash flow, and positioning for 2015, which involve risks and uncertainties that could cause actual results to differ materially from those currently anticipated. Risks and uncertainties that may affect future results include those that are described from time to time in the Company’s SEC filings. These forward-looking statements represent the judgment of the Company, as of the date of this release, and Mobile Mini disclaims any intent or obligation to update forward-looking statements.

(See accompanying tables)

Reclassifications:

Certain amounts in the consolidated statements of operations for the three months ended March 31, 2015, which is included in the year-to-date period ended June 30, 2015, have been reclassified to conform to the current period presentation. The reclassifications have no effect on total revenues, loss from operations, net loss or net loss per common share.

The Company believes the current presentation better reflects the nature of the underlying financial statement items.

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Condensed Consolidated Statements of Operations

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Condensed Consolidated Statements of Operations

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Operating Data

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Product Line Information – Adjusted (1)

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Condensed Consolidated Balance Sheets

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Condensed Consolidated Statements of Cash Flows

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Non-GAAP Financial Information

In addition to disclosing financial results that are determined in accordance with U.S. generally accepted accounting principles (“GAAP”), the Company also discloses in this press release certain non-GAAP financial information. These financial measures are not recognized measures under GAAP and they are not intended to be and should not be considered in isolation or as a substitute for, or superior to, the financial information prepared and presented in accordance with GAAP. EBITDA, adjusted EBITDA, EBITDA margin, adjusted EBITDA margin, adjusted net income, adjusted diluted earnings per share, and free cash flow are non-GAAP financial measures as defined by Securities and Exchange Commission (“SEC”) rules. This non-GAAP financial information may be determined or calculated differently by other companies. Reconciliations of these measurements to the most directly comparable GAAP financial measures are as follows:

Mobile Mini, Inc.

Adjusted EBITDA GAAP Reconciliations

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(in thousands)

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Free Cash Flow GAAP Reconciliation

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EBITDA and adjusted EBITDA. EBITDA is defined as net income before discontinued operations, net of tax (if applicable), interest expense, income taxes, depreciation and amortization, and debt restructuring or extinguishment expense (if applicable), including any write-off of deferred financing costs. Adjusted EBITDA further excludes certain non-cash expenses, including share-based compensation, as well as transactions that management believes are not indicative of our ongoing business. Because EBITDA and adjusted EBITDA, as defined, exclude some but not all items that affect our cash flow from operating activities, they may not be comparable to similarly titled performance measures presented by other companies.

We present EBITDA and adjusted EBITDA because we believe they provide useful information regarding our ability to meet our future debt payment requirements, capital expenditures and working capital requirements and that they provide an overall evaluation of our financial condition. EBITDA and adjusted EBITDA have certain limitations as analytical tools and should not be used as substitutes for net income, cash flows from operations, or other consolidated income or cash flow data prepared in accordance with GAAP.

EBITDA and adjusted EBITDA margins are calculated as EBITDA and adjusted EBITDA divided by total revenues expressed as a percentage. The GAAP financial measure that is most directly comparable to EBITDA margin is operating margin, which represents operating income divided by revenues.

Free Cash Flow. Free cash flow is defined as net cash provided by operating activities, minus or plus, net cash used in or provided by investing activities, excluding acquisitions and certain transactions. Free cash flow is a non-GAAP financial measure and is not intended to replace net cash provided by operating activities, the most directly comparable financial measure prepared in accordance with GAAP. We present free cash flow because we believe it provides useful information regarding our liquidity and ability to meet our short-term obligations. In particular, free cash flow indicates the amount of cash available after capital expenditures for, among other things, investments in our existing business, debt service obligations, payment of authorized quarterly dividends, repurchase of our common stock and strategic small acquisitions.

Earlier in this release, we provided a reconciliation of these adjusted measurements to actual results along with a reconciliation of net income to EBITDA and adjusted EBITDA, net cash provided by operating activities to EBTIDA and net cash provided by operating activities to free cash flow.