Exhibit 99.1

INSIGHT ENTERPRISES, INC. REPORTS FIRST QUARTER 2014 RESULTS

TEMPE, AZ – May 1, 2014 – Insight Enterprises, Inc. (NASDAQ: NSIT) (the “Company”) today reported results of operations for the quarter ended March 31, 2014.

For the first quarter of 2014

“In the first quarter, solid sales execution and strict cost discipline combined with improving demand trends globally resulted in strong double digit earnings growth year over year,” stated Ken Lamneck, President and Chief Executive Officer. “We are pleased with our first quarter results and the sales and operational discipline we are seeing in our business and expect that will serve us well as we head through the balance of the year,” added Lamneck.

SEGMENT OVERVIEW

In North America, net sales were $780.7 million for the first quarter of 2014, an increase of 5% compared to net sales of $747.0 million for the first quarter of 2013. Net sales of hardware and software increased 4% and 11%, respectively, year over year, while net sales of services declined 14% year to year. Gross profit of $107.4 million was also up 5% year over year, with gross margin increasing to 13.8% for the first quarter of 2014 from 13.7% in the first quarter of 2013. Selling and administrative expenses in North America remained flat at $89.2 million in the first quarter of both 2014 and 2013. During the first quarter of 2014, severance and restructuring expenses recorded in North America were immaterial, compared to $1.1 million, $680,000 net of tax, during the first quarter of 2013. As a result, earnings from operations in North America increased 48% year over year to $18.2 million, or 2.3% of net sales, in the first quarter of 2014, compared to $12.3 million, or 1.6% of net sales, in the first quarter of 2013. Excluding severance and restructuring expenses in both periods, earnings from operations in North America on a non-GAAP basis increased 37% year over year to $18.2 million, or 2.3% of net sales, in the first quarter of 2014 compared to $13.3 million, or 1.8% of net sales, in the first quarter of 2013.*

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Insight Enterprises, Inc.     6820 South Harl Avenue     Tempe, Arizona 85283     800.467.4448     FAX 480.760.8958

The Company’s EMEA operating segment reported net sales of $387.9 million for the first quarter of 2014, which was flat compared to the first quarter of 2013. Excluding the effects of foreign currency movements, net sales decreased 5% year to year. Net sales of hardware increased 7% year over year, while net sales of software and services declined 3% and 13%, respectively, year to year, all in U.S. dollars. Excluding the effects of foreign currency movements, hardware net sales increased 1% year over year, and software and services net sales declined 8% and 17%, respectively, compared to the first quarter of 2013. Gross profit of $49.3 million was up 1%, with gross margin increasing to 12.7% for the first quarter of 2014 from 12.6% in the first quarter of 2013. Excluding the effects of foreign currency movements, gross profit declined 4% year to year. Selling and administrative expenses in EMEA in the first quarter of 2014 were up 3%, or $1.3 million, compared to the first quarter of 2013. Excluding the effects of foreign currency movements, selling and administrative expenses declined 2% year to year. During the first quarter of 2014, severance and restructuring expenses recorded in EMEA were immaterial, compared to $1.7 million, $1.2 million net of tax, of severance and restructuring expenses reported for the first quarter of 2013. As a result, earnings from operations in EMEA increased 66% year over year to $2.0 million, or 0.5% of net sales, in the first quarter of 2014 compared to $1.2 million, or 0.3% of net sales, in the first quarter of 2013. Excluding severance and restructuring expenses in both periods, earnings from operations in EMEA on a non-GAAP basis decreased 22% year to year to $2.2 million, or 0.6% of net sales, in the first quarter of 2014 compared to $2.9 million, or 0.7% of net sales, in the first quarter of 2013.*

The Company’s APAC operating segment reported net sales of $45.9 million for the first quarter of 2014, a decrease of 4% compared to the first quarter of 2013 in U.S. dollars. Excluding the effects of foreign currency movements, net sales increased 6% year over year. Gross profit remained flat at $7.0 million, with gross margin increasing to 15.3% for the first quarter of 2014 from 14.7% in the first quarter of 2013. Excluding the effects of foreign currency movements, gross profit increased 11% year over year. Selling and administrative expenses in APAC increased $107,000, or 2%, year over year in U.S. dollars, an increase of 14% year over year excluding the effects of foreign currency movements. As a result, earnings from operations in APAC decreased 10% year to year to $868,000, or 1.9% of net sales, in the first quarter of 2014 compared to $964,000, or 2.0% of net sales, in the first quarter of 2013.

Throughout this “Segment Overview” section, the Company refers to changes in net sales, gross profit and selling and administrative expenses in EMEA and APAC excluding the effects of foreign currency movements. In computing these changes and percentages, the Company compares the current year amount as translated into U.S. dollars under the applicable accounting standards to the prior year amount in local currency translated into U.S. dollars utilizing the average translation rate for the current period.

Net of tax amounts referenced above were computed using the statutory tax rate for the taxing jurisdictions in the operating segment in which the related expenses were recorded.

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Insight Enterprises, Inc.     6820 South Harl Avenue     Tempe, Arizona 85283     800.467.4448     FAX 480.760.8958

UPDATED GUIDANCE

For the full year of 2014, the Company continues to expect the global IT market to grow in the low- to mid-single digit range. The Company expects its business to grow slightly faster than the market. As a result, the Company expects earnings per share for the full year 2014 to be between $1.97 and $2.07.

This outlook reflects:

This outlook does not reflect severance and restructuring expenses or a non-cash impairment loss related to our Illinois real estate assets that we expect to record in the second quarter.

CONFERENCE CALL AND WEBCAST

The Company will host a conference call and live web cast today at 5:00 p.m. ET to discuss first quarter 2014 results of operations. A live web cast of the conference call (in listen-only mode) will be available on the Company’s web site at http://nsit.client.shareholder.com/events.cfm, and a replay of the web cast will be available on the Company’s web site for a limited time following the call. To listen to the live web cast by telephone, call 1-877-402-8904 if located in the U.S., 678-809-1029 for international callers, and enter the access code 32389551.

USE OF NON-GAAP FINANCIAL MEASURES

The non-GAAP financial measures exclude severance and restructuring expenses in 2014 and 2013 and the tax effect of these charges. The Company excludes these charges when internally evaluating earnings from operations, tax expense, net earnings and diluted earnings per share for the Company and earnings from operations for each of the Company’s operating segments. These non-GAAP measures are used to evaluate financial performance against budgeted amounts, to calculate incentive compensation, to assist in forecasting future performance and to compare the Company’s results to those of the Company’s competitors. The Company believes that these non-GAAP financial measures are useful to investors because they allow for greater transparency, facilitate comparisons to prior periods and the Company’s competitors’ results and assist in forecasting performance for future periods. These non-GAAP financial measures are not prepared in accordance with GAAP and may be different from non-GAAP financial measures presented by other companies. Non-GAAP financial measures should not be considered as a substitute for, or superior to, measures of financial performance prepared in accordance with GAAP.

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Insight Enterprises, Inc.     6820 South Harl Avenue     Tempe, Arizona 85283     800.467.4448     FAX 480.760.8958

FINANCIAL SUMMARY TABLE

(DOLLARS IN THOUSANDS, EXCEPT PER SHARE DATA)

(UNAUDITED)

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Insight Enterprises, Inc.     6820 South Harl Avenue     Tempe, Arizona 85283     800.467.4448     FAX 480.760.8958

FORWARD-LOOKING INFORMATION

Certain statements in this release and the related conference call and web cast are “forward-looking statements” within the meaning of the Private Securities Litigation Reform Act of 1995. Forward-looking statements, including the Company’s expectations relative to the growth of the global IT market and its expected 2014 financial results and diluted earnings per share, and the assumptions relating thereto, including the effective tax rate, the effect on gross profit of partner program changes and the expected amount and timing of a non-cash impairment loss related to the Company’s Illinois real estate assets, are inherently subject to risks and uncertainties, some of which cannot be predicted or quantified. Future events and actual results could differ materially from those set forth in, contemplated by, or underlying the forward-looking statements. There can be no assurances that the results discussed by the forward-looking statements will be achieved, and actual results may differ materially from those set forth in the forward-looking statements. Some of the important factors that could cause the Company’s actual results to differ materially from those projected in any forward-looking statements, include, but are not limited to, the following, which are discussed in “Risk Factors” in Part I, Item 1A of the Company’s Annual Report on Form 10-K for the year ended December 31, 2013:

Additionally, there may be other risks that are otherwise described from time to time in the reports that the Company files with the Securities and Exchange Commission. Any forward-looking statements in this release should be considered in light of various important factors, including the risks and uncertainties listed above, as well as others. The Company assumes no obligation to update, and, except as may be required by law, does not intend to update, any forward-looking statements. The Company does not endorse any projections regarding future performance that may be made by third parties.

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Insight Enterprises, Inc.     6820 South Harl Avenue     Tempe, Arizona 85283     800.467.4448     FAX 480.760.8958

INSIGHT ENTERPRISES, INC. AND SUBSIDIARIES

CONSOLIDATED STATEMENTS OF OPERATIONS

(IN THOUSANDS, EXCEPT PER SHARE DATA)

(UNAUDITED)

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Insight Enterprises, Inc.     6820 South Harl Avenue     Tempe, Arizona 85283     800.467.4448     FAX 480.760.8958

INSIGHT ENTERPRISES, INC. AND SUBSIDIARIES

CONSOLIDATED BALANCE SHEETS

(IN THOUSANDS)

(UNAUDITED)

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Insight Enterprises, Inc.     6820 South Harl Avenue     Tempe, Arizona 85283     800.467.4448     FAX 480.760.8958

INSIGHT ENTERPRISES, INC. AND SUBSIDIARIES

CONSOLIDATED STATEMENTS OF CASH FLOWS

(IN THOUSANDS)

(UNAUDITED)

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Insight Enterprises, Inc.     6820 South Harl Avenue     Tempe, Arizona 85283     800.467.4448     FAX 480.760.8958

INSIGHT ENTERPRISES, INC. AND SUBSIDIARIES

RECONCILIATION OF GAAP TO NON-GAAP FINANCIAL MEASURES

(IN THOUSANDS, EXCEPT PER SHARE DATA)

(UNAUDITED)

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Insight Enterprises, Inc.     6820 South Harl Avenue     Tempe, Arizona 85283     800.467.4448     FAX 480.760.8958