Certification Pursuant to Rule 30a-2(b) under the 1940 Act and Section 906
of the Sarbanes-Oxley Act

I, James M. Dykas, President and Chief Executive Officer of First Trust Exchange-Traded Fund III (the “Registrant”), certify that:

1. The Form N-CSR of the Registrant (the “Report”) fully complies with the requirements of Section 13(a) or 15(d) of the Securities Exchange Act of 1934, as amended; and

2. The information contained in the Report fairly presents, in all material respects, the financial condition and results of operations of the Registrant.

Date:	January 10, 2022	/s/ James M. Dykas
		James M. Dykas, President and Chief Executive Officer (principal executive officer)

I, Donald P. Swade, Treasurer, Chief Financial Officer and Chief Accounting Officer of First Trust Exchange-Traded Fund III (the “Registrant”), certify that:

1. The Form N-CSR of the Registrant (the “Report”) fully complies with the requirements of Section 13(a) or 15(d) of the Securities Exchange Act of 1934, as amended; and

2. The information contained in the Report fairly presents, in all material respects, the financial condition and results of operations of the Registrant.

Date:	January 10, 2022	/s/ Donald P. Swade
		Donald P. Swade, Treasurer, Chief Financial Officer and Chief Accounting Officer (principal financial officer)