UNITED STATES
                       SECURITIES AND EXCHANGE COMMISSION
                             Washington, D.C. 20549

                                   FORM N-Q

                   QUARTERLY SCHEDULE OF PORTFOLIO HOLDINGS
    OF REGISTERED MANAGEMENT INVESTMENT COMPANY



  Investment Company Act file number 811-21664


                         Pioneer Series Trust III
               (Exact name of registrant as specified in charter)


                       60 State Street, Boston, MA 02109
              (Address of principal executive offices) (ZIP code)


            Terrence J. Cullen, Pioneer Investment Management, Inc.,
                       60 State Street, Boston, MA 02109
                    (Name and address of agent for service)


Registrant's telephone number, including area code:  (617) 742-7825


Date of fiscal year end:  August 31

Date of reporting period:  May 31, 2017

Form N-Q is to be used by management investment companies, other than small
business investment companies registered on Form N-5 (239.24 and 274.5 of this
chapter), to file reports with the Commission, not later than 60 days after
close of the first and third fiscal quarters, pursuant to Rule 30b1-5 under
the Investment Company Act of 1940 (17 CFR 270.30b1-5).  The Commission may
use the information provided on Form N-Q in its regulatory, disclosure review,
inspection, and policymaking roles.

A registrant is required to disclose the information specified by Form N-Q,
and the Commission will make this information public. A registrant is not
required to respond to the collection of information contained in Form N-Q
unless the Form displays a currently valid Office of Management and Budget
("OMB") control number. Please direct comments concerning the accuracy of the
information collection burden estimate and any suggestions for reducing the
burden to Secretary, Securities and Exchange Commission, 450 Fifth Street, NW,
Washington, DC 20549-0609.  The OMB has reviewed this collection of information
under the clearance requirements of 44 U.S.C. ss. 3507.


<PAGE>
ITEM 1. Schedule of Investments.

File the schedules as of the close of the reporting period as set forth in
ss. 210.12-12  12-14 of Regulation S-X [17 CFR 210.12-12  12-14]. The
schedules need not be audited.

	Pioneer Disciplined Value Fund
	Schedule of Investments 5/31/2017 (unaudited)
Shares			Value
	COMMON STOCKS - 99.6%
	Energy - 6.5%
	Integrated Oil & Gas - 4.7%
339,858	Exxon Mobil Corp.	$	27,358,569
	Oil & Gas Exploration & Production - 1.8%
467,173	Cabot Oil & Gas Corp.	$	10,366,569
	Total Energy	$	37,725,138
	Materials - 5.8%
	Fertilizers & Agricultural Chemicals - 1.7%
53,290	Agrium, Inc.	$	4,920,266
188,793	CF Industries Holdings, Inc.		5,078,532
		$	9,998,798
	Specialty Chemicals - 1.0%
53,573	PPG Industries, Inc.	$	5,698,024
	Paper Packaging - 3.1%
404,436	Sealed Air Corp.	$	17,965,047
	Total Materials	$	33,661,869
	Capital Goods - 10.7%
	Aerospace & Defense - 5.0%
173,603	Raytheon Co.	$	28,472,628
	Building Products - 3.5%
546,614	Masco Corp.	$	20,361,372
	Industrial Machinery - 2.2%
42,479	Illinois Tool Works, Inc.	$	5,998,884
76,396	Ingersoll-Rand Plc		6,845,082
		$	12,843,966
	Total Capital Goods	$	61,677,966
	Transportation - 0.8%
	Trucking - 0.8%
57,233	JB Hunt Transport Services, Inc.	$	4,886,554
	Total Transportation	$	4,886,554
	Automobiles & Components - 3.1%
	Auto Parts & Equipment - 3.1%
200,077	Delphi Automotive Plc	$	17,600,774
	Total Automobiles & Components	$	17,600,774
	Consumer Durables & Apparel - 1.9%
	Footwear - 1.9%
201,665	NIKE, Inc. (Class B)	$	10,686,228
	Total Consumer Durables & Apparel	$	10,686,228
	Media - 4.8%
	Cable & Satellite - 4.8%
659,351	Comcast Corp.	$	27,488,343
	Total Media	$	27,488,343
	Food & Staples Retailing - 3.4%
	Drug Retail - 2.9%
216,843	CVS Health Corp.	$	16,660,048
	Food Retail - 0.5%
79,623	Whole Foods Market, Inc.	$	2,786,009
	Total Food & Staples Retailing	$	19,446,057
	Food, Beverage & Tobacco - 3.9%
	Brewers - 1.2%
75,730	Molson Coors Brewing Co. (Class B)	$	7,178,447
	Packaged Foods & Meats - 2.7%
146,585	McCormick & Co., Inc.	$	15,266,828
	Total Food, Beverage & Tobacco	$	22,445,275
	Health Care Equipment & Services - 4.6%
	Health Care Supplies - 2.5%
64,654	The Cooper Companies, Inc.	$	14,143,062
	Managed Health Care - 2.1%
169,446	Centene Corp. *	$	12,306,863
	Total Health Care Equipment & Services	$	26,449,925
	Pharmaceuticals, Biotechnology & Life Sciences - 7.8%
	Pharmaceuticals - 7.8%
162,455	Johnson & Johnson	$	20,834,854
748,867	Pfizer, Inc.		24,450,508
		$	45,285,362
	Total Pharmaceuticals, Biotechnology & Life Sciences	$	45,285,362
	Banks - 12.2%
	Diversified Banks - 7.2%
376,840	JPMorgan Chase & Co.	$	30,957,404
204,092	US Bancorp		10,386,242
		$	41,343,646
	Regional Banks - 5.0%
242,919	The PNC Financial Services Group, Inc.	$	28,834,485
	Total Banks	$	70,178,131
	Diversified Financials - 11.4%
	Consumer Finance - 1.4%
292,422	Synchrony Financial	$	7,851,531
	Asset Management & Custody Banks - 5.7%
66,453	BlackRock, Inc.	$	27,195,226
180,059	Invesco, Ltd.		5,707,870
		$	32,903,096
	Investment Banking & Brokerage - 3.3%
500,048	The Charles Schwab Corp.	$	19,376,860
	Financial Exchanges & Data - 1.0%
82,032	Nasdaq, Inc.	$	5,549,465
	Total Diversified Financials	$	65,680,952
	Insurance - 4.8%
	Insurance Brokers - 3.2%
234,649	Marsh & McLennan Companies, Inc.	$	18,199,376
	Property & Casualty Insurance - 1.6%
65,527	Chubb, Ltd.	$	9,382,811
	Total Insurance	$	27,582,187
	Software & Services - 2.7%
	Internet Software & Services - 2.7%
458,536	eBay, Inc. *	$	15,727,785
	Total Software & Services	$	15,727,785
	Technology Hardware & Equipment - 4.6%
	Communications Equipment - 3.0%
546,769	Cisco Systems, Inc.	$	17,239,627
	Computer Storage & Peripherals - 1.6%
60,517	Apple, Inc.	$	9,244,577
	Total Technology Hardware & Equipment	$	26,484,204
	Semiconductors & Semiconductor Equipment - 3.7%
	Semiconductors - 3.7%
607,862	Taiwan Semiconductor Manufacturing Co., Ltd. (A.D.R.)	$	21,494,000
	Total Semiconductors & Semiconductor Equipment	$	21,494,000
	Telecommunication Services - 2.2%
	Integrated Telecommunication Services - 2.2%
507,975	CenturyLink, Inc.	$	12,673,976
	Total Telecommunication Services	$	12,673,976
	Utilities - 4.7%
	Electric Utilities - 4.7%
380,927	American Electric Power Co., Inc.	$	27,342,940
	Total Utilities	$	27,342,940
	TOTAL COMMON STOCKS
	(Cost $520,291,472)	$	574,517,666
	TOTAL INVESTMENT IN SECURITIES - 99.6%
	(Cost $520,291,472) (a)	$	574,517,666
	OTHER ASSETS & LIABILITIES - 0.4%	$	2,480,546
	NET ASSETS - 100.0%	$	576,998,212
*	Non-income producing security.
(A.D.R.)	American Depositary Receipts.
(a)	At May 31, 2017, the net unrealized appreciation on investments based on
	cost for federal income tax purposes of $521,396,101 was as follows:
	Aggregate gross unrealized appreciation for all investments in which
	there is an excess of value over tax cost	$	59,593,683
	Aggregate gross unrealized depreciation for all investments in which
	there is an excess of tax cost over value		(6,472,118)
	Net unrealized appreciation	$	53,121,565

Various inputs are used in determining the value of the Fund's investments.  These inputs are summarized in the three broad levels listed below.

Level 1 – quoted prices in active markets for identical securities.

Level 2 – other significant observable inputs (including quoted prices for similar securities, interest rates, prepayment speeds, credit risk, etc.).

Level 3 – significant unobservable inputs (including the Fund's own assumptions in determining fair value of investments).

The following is a summary of the inputs used as of May 31, 2017, in valuing the Fund's investments:

	Level 1		Level 2		Level 3		Total
Common Stocks	$	574,517,666	$	-	$	-	$	574,517,666
Total	$	574,517,666	$	-	$	-	$	574,517,666
During the period ended May 31, 2017, there were no transfers between Levels 1, 2 and 3.

ITEM 2. CONTROLS AND PROCEDURES. (a) Disclose the conclusions of the registrant's principal executive and principal financial officers, or persons performing similar functions, regarding the effectiveness of the registrant's disclosure controls and procedures (as defined in Rule 30a-3(c) under the Act (17 CFR 270.30a-3(c))) as of a date within 90 days of the filing date of the report that includes the disclosure required by this paragraph, based on the evaluation of these controls and procedures required by Rule 30a-3(b) under the Act (17 CFR 270.30a-3(b))) and Rule 13a-15(b) or 15d-15(b) under the Exchange Act (17 CFR 240.13a-15(b) or 240.15d-15(b)). The registrant's principal executive officer and principal financial officer have concluded that the registrant's disclosure controls and procedures are effective based on their evaluation of these controls and procedures as of a date within 90 days of the filing date of this report. (b) Disclose any change in the registrant's internal controls over financial reporting (as defined in Rule 30a-3(d) under the Act (17 CFR 270.30a-3(d)) that occurred during the registrant's last fiscal quarter that has materially affected, or is reasonably likely to materially affect, the registrant's internal control over financial reporting. There were no significant changes in the registrant's internal control over financial reporting that occurred during the second fiscal quarter of the period covered by this report that have materially affected, or are reasonably likely to materially affect, the registrant's internal control over financial reporting. ITEM 3. EXHIBITS. File as exhibits as part of this Form a separate certification for each principal executive officer and principal financial officer of the registrant as required by Rule 30a-2(a) under the Act (17 CFR 270.30a-2(a)), exactly as set forth below: CERTIFICATIONS I, [identify the certifying individual], certify that: 1. I have reviewed this report on Form N-Q of [identify registrant]; 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; 3. Based on my knowledge, the schedules of investments included in this report fairly present in all material respects the investments of the registrant as of the end of the fiscal quarter for which the report is filed; 4. The registrants other certifying officer(s) and I are responsible for establishing and maintaining disclosure controls and procedures (as defined in Rule 30a-3(c) under the Investment Company Act of 1940) and internal control over financial reporting (as defined in Rule 30a-3(d) under the Investment Company Act of 1940) for the registrant and have: (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; (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; (c) Evaluated the effectiveness of the registrants disclosure controls and procedures and presented in this report our conclusions about the effectiveness of the disclosure controls and procedures, as of a date within 90 days prior to the filing date of this report, based on such evaluation; and (d) Disclosed in this report any change in the registrants internal control over financial reporting that occurred during the registrants most recent fiscal quarter that has materially affected, or is reasonably likely to materially affect, the registrants internal control over financial reporting; and 5. The registrants other certifying officer(s) and I have disclosed to the registrants auditors and the audit committee of the registrants board of directors (or persons performing the equivalent functions): (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 registrants ability to record, process, summarize, and report financial information; and (b) Any fraud, whether or not material, that involves management or other employees who have a significant role in the registrants internal control over financial reporting. Date: [Signature] [Title] Filed herewith. <PAGE> SIGNATURES [See General Instruction F] Pursuant to the requirements of the Securities Exchange Act of 1934 and the Investment Company Act of 1940, the registrant has duly caused this report to be signed on its behalf by the undersigned, thereunto duly authorized. (Registrant) Pioneer Series Trust III By (Signature and Title)* /s/ Lisa M.Jones ----------------------- Lisa M.Jones, President and Chief Executive Officer Date July 27, 2017 Pursuant to the requirements of the Securities Exchange Act of 1934 and the Investment Company Act of 1940, this report has been signed below by the following persons on behalf of the registrant and in the capacities and on the dates indicated. By (Signature and Title)* /s/ Lisa M.Jones ----------------------- Lisa M.Jones, President and Chief Executive Officer Date July 27, 2017 By (Signature and Title)* /s/ Mark E. Bradley ----------------- Mark E. Bradley, Treasurer and Chief Accounting and Financial Officer Date July 27, 2017 * Print the name and title of each signing officer under his or her signature.