Exhibit 99.1

WILLIAM LYON HOMES REPORTS THIRD QUARTER 2015 RESULTS

114% INCREASE IN NET INCOME AVAILABLE TO COMMON STOCKHOLDERS; 49% INCREASE IN ORDERS; AND 33% INCREASE IN DELIVERIES

NEWPORT BEACH, CA — November 6, 2015 — William Lyon Homes (NYSE: WLH), a leading homebuilder in the Western U.S., announced results for its 2015 third quarter ended September 30, 2015.

2015 Third Quarter Highlights (Comparison to 2014 Third Quarter)

“In the third quarter, we continued to show significant year-over-year improvement in net new home orders, the dollar value of orders, deliveries and revenue, resulting in net income available to common stockholders of $12.1 million, or $0.31 per diluted share, up 114% over the same quarter last year,” said William H. Lyon, Co-Chief Executive Officer. “We continue to see healthy demand and limited supply across our markets, and we believe that we are well positioned to finish the year strong as we remain focused on executing our financial and operational objectives.”

“We delivered another quarter of year-over-year improvement in our key operational metrics, while achieving our objective of growing our community count, which averaged 73 for the quarter, up 49% from the third quarter of 2014, and stood at 77 at quarter end,” said Matthew R. Zaist, Co-Chief Executive Officer and President. “Due to a number of market factors, our backlog conversion rate for the third quarter was below our expectations, and we are focused on improving upon that over the balance of the year in the face of a challenging labor market. Our backlog stood at 1,032 homes with a corresponding value of $537.1 million as of September 30^th, providing an opportunity to achieve meaningful revenue and earnings growth as we focus on converting our backlog into deliveries during the fourth quarter.”

Operating Results

Home sales revenue for the third quarter of 2015 was $244.3 million, as compared to $196.1 million in the year-ago period, an increase of 25%. The increase was driven by a 33% increase in deliveries to 564 homes, compared to 424 in the third quarter of 2014, offset by a decrease in the average sales price of homes delivered of $433,200, compared to $462,500 in the year-ago period. The decline in ASP reflects changes in geographic and product mix.

The dollar value of orders for the third quarter of 2015 was $298.4 million, an increase of 50%, from $199.2 million in the year-ago period. Net new home orders for the quarter were 628, up 49% from the third quarter of 2014. The increase in net new home orders was driven by a 49% increase in community count to 73 average sales locations, from 49 in the year-ago period, and the average monthly absorption rate was flat year-over-year at 2.9 sales per community.

The dollar value of homes in backlog was $537.1 million as of September 30, 2015, an increase of 40% compared to $382.9 million as of September 30, 2014. The increase was driven by a 42% increase in units in backlog to 1,032 from 728 in the year-ago period. In addition, our ASP in backlog as of September 30, 2015 was 20% higher than the ASP of homes closed in the third quarter.

Adjusted homebuilding gross margin percentage was 24.7% during the third quarter of 2015. Homebuilding gross margins for the quarter were 18.0%. In conjunction with the adoption of purchase accounting related to the Polygon acquisition, GAAP margins were impacted by approximately 330 basis points during the quarter.

SG&A expense during the third quarter of 2015 was 12.0% of homebuilding revenue, compared with 12.9% in the year-ago quarter, an improvement of 90 basis points. Breaking down the components of SG&A, sales and marketing expense was 6.3% of homebuilding revenue during the quarter, compared to 6.4% in the year-ago quarter. General administrative expenses decreased to 5.7% of homebuilding revenue, compared to 6.5% in the year-ago quarter, as we continued to benefit from a larger operating platform with a lower relative cost structure.

Balance Sheet Update

At quarter end, cash, cash equivalents and restricted cash totaled $26.9 million, escrow proceeds receivable totaled $5.8 million, real estate inventories totaled $1.7 billion, total assets were $2.0 billion and total equity was $638.3 million. Net debt to net book capitalization was 63.6%, and total debt to total book capitalization was 64.2% at September 30, 2015.

Conference Call

The Company will host a conference call to discuss these results today, Friday, November 6, 2015 at 9:00 a.m. Pacific Time. The call will be available via both the telephone at (855) 851-4524 or (720) 634-2900, passcode #69399971, or through the Company’s website at www.lyonhomes.com in the Investor Relations section of the site. A replay of the call will be available through November 13, 2015 by dialing (855) 859-2056 or (404) 537-3406, passcode #69399971. A webcast replay of the call will also be available on the Company’s website approximately two hours after the broadcast.

About William Lyon Homes

William Lyon Homes is one of the largest Western U.S. regional homebuilders. Headquartered in Newport Beach, California, the Company is primarily engaged in the design, construction, marketing and sale of single-family detached and attached homes in California, Arizona, Nevada, Colorado, Washington and Oregon. Its core markets include Orange County, Los Angeles, San Diego, the San Francisco Bay Area, Phoenix, Las Vegas, Denver, Seattle and Portland. The Company has a distinguished legacy of more than 59 years of homebuilding operations, over which time it has sold in excess of 95,000 homes. The Company markets and sells its homes under the William Lyon Homes brand in all of its markets except for Colorado, where the Company operates under the Village Homes brand, and Washington and Oregon, where the Company operates under the Polygon Northwest brand.

Certain statements contained in this release and the accompanying comments during our conference call that are not historical information contain forward-looking statements, including, but not limited to, statements related to: market and industry trends, the anticipated financial and operating results from execution of the Company’s growth strategy and focus on markets in the Western United States, the continued housing market recovery, expected community count growth, anticipated operating results for the fourth quarter of 2015, anticipated ASP, expected SG&A percentage, gross margins, future cash needs and liquidity, leverage ratios and backlog conversion rates. The forward-looking statements involve risks and uncertainties and actual results may differ materially from those projected or implied. The Company makes no commitment, and disclaims any duty, to update or revise any forward-looking statements to reflect future events or changes in these expectations. Further, certain forward-looking statements are based on assumptions of future events which may not prove to be accurate. Factors that may impact such forward-looking statements include, among others: the availability of labor and homebuilding materials; adverse weather conditions, including the continued drought in California; our ability to realize the anticipated benefits from the acquisition of Polygon Northwest; our ability to integrate successfully the Polygon Northwest operation with our existing operations; worsening in general economic conditions either internationally, nationally or in regions in which we operate; conditions in our newly entered markets and newly acquired operations; worsening in markets for residential housing; decline in real estate values resulting in impairment of our real estate assets; volatility in the banking industry and credit markets; uncertainties in the capital and securities markets; terrorism or other hostilities involving the United States; building moratorium or “slow-growth” or “no-growth” initiatives that could be implemented in states in which we operate; whether an ownership change occurred that could, under certain circumstances, have resulted in the limitation of our ability to offset prior years’ taxable income with net operating losses; changes in mortgage and other interest rates; conditions in the capital, credit and financial markets, including mortgage lending standards and the availability of mortgage financing; changes in generally accepted accounting principles or interpretations of those principles; changes in prices of homebuilding materials; competition for home sales from other sellers of new and resale homes; cancellations and our ability to realize our backlog; the occurrence of events such as landslides, soil subsidence and earthquakes that are uninsurable, not economically insurable or not subject to effective indemnification agreements; changes in governmental laws and regulations; our financial leverage and level of indebtedness and any inability to comply with financial and other covenants under our debt instruments; whether we are able to refinance the outstanding balances of our debt obligations at their maturity; anticipated tax refunds; limitations on our ability to utilize our tax attributes; limitations on our ability to reverse any remaining portion of our valuation allowance with respect to our deferred tax assets; the timing of receipt of regulatory approvals and the

opening of projects; the impact of construction defect, product liability and home warranty claims, including the adequacy of self-insurance accruals, and the applicability and sufficiency of our insurance coverage; the availability and cost of land for future development; and additional factors discussed under the sections captioned “Risk Factors” included in our annual and quarterly reports filed with the Securities and Exchange Commission. The foregoing list is not exhaustive. New risk factors may emerge from time to time and it is not possible for management to predict all such risk factors or to assess the impact of such risk factors on our business.

Investor/Media Contacts:

Larry Clark

Financial Profiles, Inc.

(310) 622-8223

WLH@finprofiles.com

WILLIAM LYON HOMES

CONSOLIDATED STATEMENTS OF OPERATIONS

(in thousands except number of shares and per share data)

(unaudited)

WILLIAM LYON HOMES

CONSOLIDATED STATEMENTS OF OPERATIONS

(in thousands except number of shares and per share data)

(unaudited)

WILLIAM LYON HOMES

CONSOLIDATED BALANCE SHEETS

(in thousands, except number of shares and par value per share)

WILLIAM LYON HOMES

SELECTED FINANCIAL AND OPERATING INFORMATION

(unaudited)

WILLIAM LYON HOMES

SELECTED FINANCIAL AND OPERATING INFORMATION

(unaudited)

WILLIAM LYON HOMES

SELECTED FINANCIAL AND OPERATING INFORMATION

(unaudited)

WILLIAM LYON HOMES

SUPPLEMENTAL FINANCIAL INFORMATION

(dollars in thousands)

(unaudited)

Balance Sheet Data

WILLIAM LYON HOMES

SUPPLEMENTAL FINANCIAL INFORMATION

(dollars in thousands)

(unaudited)