Exhibit 12.1



Certification of the Chief Executive
Officer of

ESSA Pharma Inc.

Pursuant to Section 302 of the Sarbanes-Oxley
Act of 2002



CERTIFICATIONS



I, David Parkinson, certify that:



| | 1. | I have reviewed this annual report on Form 20-F of ESSA Pharma Inc. (the "Company");
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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 Company as of, and for, the periods
presented in this report;
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| | 4. | The Company's other certifying officer 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)) and internal control over financial reporting (as defined in Exchange
Act Rules 13a-15(f) and 15d-15(f)) for the Company 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 Company, 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) | Designed such internal control over financial reporting, or caused such internal control over financial reporting to be designed
under our supervision, to provide reasonable assurance regarding the reliability of financial reporting and the preparation of
financial statements for external purposes in accordance with generally accepted accounting principles;
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| | (c) | Evaluated the effectiveness of the Company'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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| | (d) | Disclosed in this report any change in the Company's internal control over financial reporting that occurred during the period
covered by the annual report that has materially affected, or is reasonably likely to materially affect, the Company's internal
control over financial reporting; and
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| | 5. | The Company's other certifying officer and I have disclosed, based on our most recent evaluation of internal control over financial
reporting, to the Company's auditors and the audit committee of the Company'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 Company'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 Company's
internal control over financial reporting.
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Date: December 11, 2017



| | /s/ David Parkinson    
| | -----------------------
| | David Parkinson        
| | Chief Executive Officer
| | ESSA Pharma Inc.