Exhibit 31.1

| CERTIFICATION OF CHIEF EXECUTIVE OFFICER                                                                     |
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| I, Simon F. Nynens, President and Chief Executive Officer   of Wayside Technology Group, Inc., certify that: |
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| 1.                                                                                                           | I have reviewed this annual report on Form 10-K of   Wayside Technology Group, Inc; |
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| 2.                                                                                                           | Based on my knowledge, this  report does not contain any untrue statement of a material fact   or omit to state a material fact necessary to make the statements made, in   light of the circumstances under which such statements were made, not   misleading with respect to the period covered by this  report; |
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| 3.                                                                                                           | Based on my knowledge, the financial statements, and   other financial information included in this    report, fairly present in all material respects the financial condition,   results of operations and cash flows of the registrant as of, and for, the   periods presented in this  report; |
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| 4.                                                                                                           | The registrant’s other certifying officers and I are   responsible for establishing and maintaining disclosure controls and procedures   (as defined in Exchange Act Rules 13a-15(e) and 15d-15(e)), for the   registrant and have: |
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|                                                                                                         | a) | designed such disclosure controls and procedures, or   caused such disclosure controls and procedures to be designed under our   supervision, to ensure that material information relating to the registrant,   including its consolidated subsidiaries, is made known to us by others within   those entities, particularly during the period in which this  report is being prepared; |
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|                                                                                                         | b) | evaluated the effectiveness of the registrant’s   disclosure controls and procedures and presented in this report our   conclusions about the effectiveness of the disclosure controls and   procedures, as of the end of the period covered by this report based on such   evaluation; and |
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|                                                                                                         | c) | disclosed in this report any change in the registrant’s   internal control over financial reporting that occurred during the   registrant’s most recent fiscal quarter (the registrant’s fourth fiscal   quarter in the case of an annual report) that has materially affected, or is   reasonably likely to materially affect, the registrant’s internal control   over financial reporting; and |
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| 5.                                                                                                           | The registrant’s other certifying officers and I have   disclosed, based on our most recent evaluation, to the registrant’s auditors   and the audit committee of the registrant’s board of directors (or persons   performing the equivalent functions): |
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|                                                                                                         | a) | all significant deficiencies and material weaknesses in   the design or operation of internal control over financial reporting which   are reasonably likely to adversely affect the registrant’s ability to record,   process, summarize and report financial information; and |
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|                                                                                                         | b) | any fraud, whether or not material, that involves   management or other employees who have a significant role in the registrant’s   internal control over financial reporting. |

| Date:  March 12,   2007              |   |
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| /s/  Simon F.   Nynens               |   |
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| Simon F. Nynens                           |   |
| President and Chief Executive Officer and |   |
| Chairman of the Board                     |   |