Exhibit 99.1

WILLIAM LYON HOMES REPORTS THIRD QUARTER 2018 RESULTS

29% INCREASE IN NET NEW HOME ORDERS; 24% INCREASE IN NEW HOME DELIVERIES;

32% INCREASE IN UNITS IN BACKLOG

NEWPORT BEACH, CA— October 30, 2018 — William Lyon Homes (NYSE: WLH), a leading homebuilder in the Western U.S., announced results for its third quarter ended September 30, 2018.

2018 Third Quarter Highlights (Comparison to 2017 Third Quarter)

“We are pleased with our financial results for the third quarter, with homebuilding revenues of $533.5 million, up 9% and new home deliveries of 1,053, up 24%,” said Matthew R. Zaist, President and Chief Executive Officer. “During the quarter, our GAAP homebuilding gross margins were 18.2%, which is a 10 basis point improvement over the third quarter of 2017, and a 30 basis point improvement sequentially from the second quarter of this year. We expect our sequential margin improvement to carry into the fourth quarter with GAAP gross margins anticipated to expand approximately 40 to 60 basis points over the third quarter. Our third quarter net new home orders were up 29% year-over-year, to 1,001, and our average number of sales locations for the third quarter was 116, up from 86 in the third quarter of 2017.”

Mr. Zaist continued, “While the long-term fundamentals remain positive in the broader economy as well as our local markets, the cost of home ownership has increased with the significant price appreciation in several of our markets over the last few years, combined with the recent rise in mortgage interest rates. As a result, and most notably in Northern California and Seattle, we have experienced some sales pace moderation, which has led us to adjust our expectations for our fourth quarter results. Overall, in the face of some challenging market conditions, our strong backlog of 1,596 units with a dollar value of over $800 million still puts us in position to finish the year strongly and achieve another year of profitability growth for the Company and a record year in revenue and deliveries. The Company expects fourth quarter results to include backlog conversion of 85% to 92.5%, which we believe will contribute significant cash in-flows in the fourth quarter, enabling us to make further progress on our debt reduction for the year and keep us on track toward our long-term balance sheet goals including targeting 40% debt-to-cap by 2020. Looking forward, our new community openings over the next several quarters will be focused on affordable price points below the market medians with an emphasis on the entry level and active adult buyer segments, which we believe will help to address affordability concerns and drive continued growth for William Lyon Homes.”

Outlook

For the fourth quarter of 2018, the Company anticipates fourth quarter new home deliveries of approximately 1,360 to 1,475 units, average sales price of homes closed of approximately $505,000, and pre-tax income before non-controlling interest of approximately $62 million to $67 million.

For the full year, the Company anticipates new home deliveries of approximately 4,235 to 4,350 units, home sales revenues of approximately $2.115 billion to $2.165 billion and pre-tax income before non-controlling interest of approximately $157 million to $162 million.

Operating Results

Home sales revenue for the third quarter of 2018 was $533.5 million, as compared to $490.3 million in the year-ago period, an increase of 9%. The increase was driven by a 24% increase in deliveries to 1,053 homes, compared to 851 in the third quarter of 2017.

Net new home orders for the quarter were 1,001, up 29% from 774 in the third quarter of 2017. The overall increase in net new home orders was driven by an increase in community count to 116 average sales locations, from 86 in the year-ago period, an increase of 35%.

The dollar value of homes in backlog was $800.6 million as of September 30, 2018, an increase of 14%, compared to $699.3 million as of September 30, 2017. The increase was driven by a 32% increase in units in backlog to 1,596 from 1,208 in the year-ago period. The average sales price of homes in backlog decreased to $501,600 from $578,900 in the prior year, due to the number of homes in backlog at our Texas division of 248 homes at an average sales price of $275,300, with no comparable amount in the prior year.

Homebuilding gross margin percentage for homes closed during the third quarter of 2018 was 18.2%, up 10 basis points from 18.1% in the third quarter of 2017, and up 30 basis points from 17.9% in the second quarter of 2018.

Sales and marketing expense during the third quarter of 2018 was 5.4% of homebuilding revenue, compared to 4.5% in the year-ago quarter, which is driven by an increase in advertising and outside broker commissions of 60 basis points combined, as well as the impact of the adoption of ASC 606 of 20 basis points, which was adopted on January 1, 2018, requiring the Company to record certain selling costs that were previously recorded as cost of sales to sales and marketing expense. General and administrative expenses increased to 5.6% of homebuilding revenue, compared to 4.7% in the year-ago quarter as a result of continued investment in our growing operating business, incremental information technology investment and further investment in building out our financial services group.

Balance Sheet Update

At quarter end, cash and cash equivalents totaled $50.8 million, owned real estate inventories totaled $2.4 billion, total assets were $2.9 billion and total equity was $1.0 billion. Total debt to book capitalization was 60.3%, and net debt to net book capitalization was 59.5% at September 30, 2018, compared to 57.1% and 56.1% at September 30, 2017, and 54.5% and 49.6% at December 31, 2017, respectively.

Conference Call

The Company will host a conference call to discuss these results today, Tuesday, October 30, 2018 at 9:00 a.m. Pacific Time. The call will be available via both the telephone at (855) 851-4524 or (720) 634-2900, conference ID #1076946, 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 6, 2018 by dialing (855) 859-2056 or (404) 537-3406, conference ID #1076946. 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, Oregon, and Texas. Its core markets include Orange County, Los Angeles, the Inland Empire, the San Francisco Bay Area, Phoenix, Las Vegas, Denver, Portland, Seattle, Austin and San Antonio. The Company has a distinguished legacy of more than 60 years of homebuilding operations, over which time it has sold in excess of 105,000 homes. The Company markets and sells its homes under the William Lyon Homes brand in all of its markets except for Washington and Oregon, where the Company operates under the Polygon Northwest brand.

Forward-Looking Statements

Certain statements contained in this release and the accompanying comments during our conference call that are not historical information may constitute “forward-looking statements” as defined by the Private Securities Litigation Reform Act of 1995, including, but not limited to, forward-looking statements related to: anticipated deliveries, revenue and pre-tax income, gross margin performance, backlog conversion rates, operating and financial results for the fourth quarter of 2018 and beyond, community count growth and project performance, market and industry trends, the continued housing market recovery, average sale price of homes to be closed in various periods, SG&A percentage, future cash needs and liquidity, minority interest from our homebuilding joint ventures, leverage ratios and reduction strategies, land acquisition spending, financial services and ancillary business performance and strategies; the anticipated financial or operational performance resulting from the RSI Communities transaction, and estimated new home deliveries, home sales revenue and community count on a combined Company basis. 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: changes in mortgage and other interest rates; affordability pressures; the Company’s ability to successfully integrate RSI Communities’ homebuilding operations with its existing operations; adverse weather conditions; the availability of labor and homebuilding materials and increased construction cycle times; our financial leverage and level of indebtedness and any inability to comply with financial and other covenants under our debt instruments; continued volatility and worsening in general economic conditions either internationally, nationally or in regions in which we operate; increased housing supply in our markets; increased outside broker costs; increased costs of homebuilding materials; changes in governmental laws and regulations and compliance, increased costs, fees and delays associated therewith; government actions, policies, programs and regulations directed at or affecting the housing market (including the Tax Cuts and Jobs Act (“TCJA”), the Dodd-Frank Act, tax benefits associated with purchasing and owning a home, and the standards, fees and size limits applicable to the purchase or insuring of mortgage loans by government-sponsored enterprises and government agencies), the homebuilding industry, or construction activities; changes in existing tax laws or enacted corporate income tax rates, including pursuant to the TCJA; worsening in markets for residential housing; 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; defects in manufactured products or other homebuilding materials; decline in real estate values resulting in impairment of our real estate assets; volatility in the banking industry, credit and capital markets; restraints on foreign investment; terrorism or other hostilities involving the United States and other geopolitical risk as well as restrictive policies such as tariffs or capital investment restrictions; building moratorium or “slow-growth” or “no-growth” initiatives that could be implemented in states in which we operate; conditions in the capital, credit and financial markets, including mortgage lending standards and the availability of and timing mortgage financing; changes in generally accepted accounting principles or interpretations of those principles; 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; limitations on our ability to utilize our tax attributes; 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; the timing of receipt of regulatory approvals and the opening of projects; 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)

WILLIAM LYON HOMES

SUPPLEMENTAL FINANCIAL INFORMATION

(dollars in thousands)

(unaudited)

WILLIAM LYON HOMES

SUPPLEMENTAL FINANCIAL INFORMATION

(dollars in thousands)

(unaudited)

WILLIAM LYON HOMES

SUPPLEMENTAL FINANCIAL INFORMATION

(dollars in thousands)

(unaudited)

Adjusted pre-tax income means income before provision for income taxes plus transaction expenses and loss for the extinguishment of the 8.5% Senior Notes. Adjusted pre-tax income is not a financial measure prepared in accordance with U.S. GAAP. Adjusted pre-tax income is presented herein because management believes the presentation of adjusted pre-tax income provides useful information to the Company’s investors regarding the Company’s results of operations because adjusted pre-tax income isolates the impact of the one-time, non-recurring transaction expenses and infrequent extinguishment fees. Adjusted pre-tax income should not be considered as an alternative for net income, cash flows from operating activities and other consolidated income or cash flow statement data prepared in accordance with accounting principles generally accepted in the United States or as a measure of profitability or liquidity. A reconciliation of income before provision for income taxes to adjusted pre-tax income is provided in the following table: