Exhibit 99.1

INSIGHT ENTERPRISES, INC. REPORTS FOURTH QUARTER AND FULL YEAR 2013 RESULTS

TEMPE, AZ – February 12, 2014 – Insight Enterprises, Inc. (NASDAQ: NSIT) (the “Company”) today reported results of operations for the quarter and year ended December 31, 2013.

For the fourth quarter of 2013 compared to the fourth quarter of 2012:

For the full year 2013 compared to the full year 2012:

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“We are pleased with our financial results in the fourth quarter. We returned to year over year growth on the top line in North America and EMEA, we executed better than expected against recently announced partner program changes, and we continued to control our operating costs, which all led to solid results in the quarter,” stated Ken Lamneck, President and Chief Executive Officer. “As we head into 2014, the foundation of our business is stronger. The integration of our IT systems in North America and EMEA is complete, and we have a strong management team in place. Market demand is improving, particularly in North America, our largest segment, and we have a healthy balance sheet to support growth. We believe we are well positioned heading into to the new year,” added Lamneck.

SEGMENT OVERVIEW

In North America, net sales were $942.8 million for the fourth quarter of 2013, an increase of 4% compared to sales of $908.3 million for the fourth quarter of 2012. Net sales of hardware and services increased 7% and 9%, respectively, year over year, while net sales of software decreased 3% year to year. Gross profit of $122.1 million was up 4% year over year, with gross margin remaining flat at 12.9%. Selling and administrative expenses in North America in the fourth quarter of 2013 remained flat, increasing by $276,000, or less than 1%, compared to the fourth quarter of 2012. During the fourth quarter of 2013, North America had $771,000, $496,000 net of tax, of severance and restructuring expenses, compared to $535,000, $336,000 net of tax, during the fourth quarter of 2012. As a result, earnings from operations in North America increased 14% year over year to $31.5 million, or 3.3% of net sales, in the fourth quarter of 2013, compared to $27.5 million, or 3.0% of net sales, in the fourth quarter of 2012. Excluding severance and restructuring expenses in both periods, earnings from operations in North America on a non-GAAP basis increased 15% year to year to $32.2 million, or 3.4% of net sales, in the fourth quarter of 2013 compared to $28.0 million, or 3.1% of net sales, in the fourth quarter of 2012.*

The Company’s EMEA operating segment reported net sales of $397.6 million for the fourth quarter of 2013, an increase of 5% in U.S. dollars compared to the fourth quarter of 2012. Excluding the effects of foreign currency movements, net sales increased 2% year over year. Net sales of hardware and software were up 2% and 7%, respectively, year over year, while net sales of services declined 5% year to year, all in U.S. dollars. Excluding the effects of foreign currency movements, hardware net sales were flat year to year while software sales increased 3% year over year and services net sales declined 7% compared to the fourth quarter of 2012. Gross profit of $49.1 million was down 3% in U.S. dollars, 6% excluding the effects of foreign currency movements, with gross margin decreasing to 12.4% for the fourth quarter of 2013 from 13.4% in the fourth quarter of 2012. Selling and administrative expenses in EMEA in the fourth quarter of 2013 were down 2%, or $851,000, compared to the fourth quarter of 2012 in U.S. dollars and, excluding the effects of foreign currency movements, were down 5% year to year. During the fourth quarter of 2013, EMEA recorded severance and restructuring expenses of $3.6 million, $3.2 million net of tax, compared to $1.3 million, $991,000 net of

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tax, reported for the fourth quarter of 2012. As a result, earnings from operations in EMEA decreased 81% year to year to $776,000, or 0.2% of net sales, in the fourth quarter of 2013 compared to $4.0 million, or 1.1% of net sales, in the fourth quarter of 2012. Excluding severance and restructuring expenses in both periods, earnings from operations in EMEA on a non-GAAP basis decreased 17% year to year to $4.4 million, or 1.1% of net sales, in the fourth quarter of 2013 compared to $5.3 million, or 1.4% of net sales, in the fourth quarter of 2012.*

The Company’s APAC operating segment reported net sales of $54.8 million for the fourth quarter of 2013, a decrease of 9% compared to the fourth quarter of 2012 in U.S. dollars, or a decrease of less than 1% excluding the effects of foreign currency movements. Gross profit was $10.0 million, a decrease of 17% year to year in U.S. dollars, 8% excluding the effects of foreign currency movements, with gross margin decreasing to 18.2% for the fourth quarter of 2013 from 20.0% in the fourth quarter of 2012. Selling and administrative expenses in APAC decreased $578,000, or 8%, year to year in U.S. dollars, but were flat excluding the effects of foreign currency movements year to year. As a result, earnings from operations in APAC decreased 28% year to year to $3.7 million, or 6.7% of net sales, in the fourth quarter of 2013 compared to $5.1 million, or 8.5% of net sales, in the fourth quarter of 2012.

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.

GUIDANCE

For the full year of 2014, the Company expects 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. The Company expects diluted 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.

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CONFERENCE CALL AND WEBCAST

The Company will host a conference call and live web cast today at 5:00 p.m. ET to discuss fourth quarter and full year 2013 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 www.insight.com, 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 55746054.

USE OF NON-GAAP FINANCIAL MEASURES

The non-GAAP financial measures exclude severance and restructuring expenses in 2013 and 2012, a gain on bargain purchase in 2012 and the tax effect of these items. 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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FINANCIAL SUMMARY TABLE

(DOLLARS IN THOUSANDS, EXCEPT PER SHARE DATA)

(UNAUDITED)

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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, capital expenditures, earnings performance 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 Company’s plans concerning the completion of its share repurchase program, 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, 2012:

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 does not intend to update, any forward-looking statements unless required by law. The Company does not endorse any projections regarding future performance made by third parties.

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INSIGHT ENTERPRISES, INC. AND SUBSIDIARIES

CONSOLIDATED STATEMENTS OF OPERATIONS

(IN THOUSANDS, EXCEPT PER SHARE DATA)

(UNAUDITED)

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INSIGHT ENTERPRISES, INC. AND SUBSIDIARIES

CONSOLIDATED BALANCE SHEETS

(IN THOUSANDS)

(UNAUDITED)

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INSIGHT ENTERPRISES, INC. AND SUBSIDIARIES

CONSOLIDATED STATEMENTS OF CASH FLOWS

(IN THOUSANDS)

(UNAUDITED)

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INSIGHT ENTERPRISES, INC. AND SUBSIDIARIES

RECONCILIATION OF GAAP TO NON-GAAP FINANCIAL MEASURES

(IN THOUSANDS, EXCEPT PER SHARE DATA)

(UNAUDITED)

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