The layoffs reached as high as the vice president level and affected divisions including cloud computing and Area 120, an internal business incubator that had already faced cuts last year, said people familiar with the matter.

The Google cuts make January the worst month yet in a wave of tech layoffs that began last year, according to estimates from Layoffs.fyi, which tracks media reports and company announcements. This week,

Microsoft Corp.

said it would eliminate 10,000 jobs, the largest layoffs in more than eight years. Online furniture seller

Wayfair Inc.

said it is laying off about 10% of its workforce, and

Unity Software Inc.,

which provides tools for creating videogames and other applications, also cut staff.

Earlier this month,

Amazon.com Inc.

said layoffs would affect more than 18,000 employees and

Salesforce Inc.

said it was laying off 10% of its workforce. Last year,

Meta Platforms Inc.

said it would cut 13% of staff.

Technology companies including Google expanded rapidly during the pandemic as life moved online. Recent cuts have been part of a broader pivot toward protecting profit and cementing the end of a growth-at-all costs era in technology. Google executives have in recent months said the company would be tightening its belt, reflecting a new period of more disciplined and efficient spending. But the company hadn’t announced cuts as deep as those of its Silicon Valley peers. 

Google hired aggressively as demand for its services rose during the health crisis, leading to more than 50% growth in total employee count across Alphabet since the end of 2019. The cuts this week appeared to fall short of the almost 12,800 employees Alphabet added to its roster in the third quarter last year.

“Over the past two years we’ve seen periods of dramatic growth. To match and fuel that growth, we hired for a different economic reality than the one we face today,” Alphabet Chief Executive

Sundar Pichai

wrote in a message to employees sent out Friday and posted on the company’s website.

“I take full responsibility for the decisions that led us here,” Mr. Pichai wrote. The corporate mea culpa for overhiring has become a recurring message in recent months at tech companies as executives realized that some of the hiring they undertook to keep pace with soaring demand for all things digital early in the pandemic left them overstaffed as the business environment soured.

Among the executives who have made such apologies are Salesforce Co-Chief Executive

Marc Benioff,

Meta Platforms CEO

Mark Zuckerberg

and Twitter Inc. co-founder

Jack Dorsey.

Alphabet recorded $17.1 billion of operating income in the third quarter last year, an 18.5% decrease from the same period in 2021. Google executives partly blamed a slowdown in revenue growth on the company’s historic performance during the tail end of the pandemic. Alphabet shares rose 4.5% to $97.24 in morning trading Friday.

Alphabet earlier this month said it would cut more than 200 jobs at its Verily Life Sciences healthcare business, accounting for about 15% of the roles at the unit. Before that, some of the last major cuts Google announced were in 2009, when the company said it was reducing the number of jobs in its sales and marketing teams by roughly 200 globally.

Activist hedge fund TCI Fund Management, which had called on Alphabet to cut costs aggressively in November, said Friday the company should go further.

“Management should aim to reduce headcount to around 150,000, which is in line with Alphabet’s headcount at the end of 2021,”

Christopher Hohn,

TCI managing director, said in a letter. “This would require a total headcount reduction in the order of 20%.”

Current and former Google employees said layoffs would likely affect the company’s famously loose and collegial culture, which has been widely imitated in the tech industry.

Google employees have long enjoyed one of the most accommodating environments among large U.S. companies. A letter to potential investors in Google’s 2004 initial public offering said the company provided many unusual benefits, such as washing machines, and would likely add more over time.

As job cuts have accumulated in the tech industry, many employees at Google have pressed executives about the possibility of layoffs at the company. At a companywide meeting in December, Mr. Pichai told employees that the company had tried to “rationalize where we can so that we are set up to better weather the storm regardless of what’s ahead.”

A Google spokesman said that Friday’s cuts would affect not just Google, but also other Alphabet subsidiaries, but didn’t specify at what levels. Alphabet subsidiaries include Verily and the Waymo self-driving-car unit. The spokesman didn’t comment on which specific products or engineering units would be affected.

“Alphabet leadership claims ‘full responsibility’ for this decision, but that is little comfort to the 12,000 workers who are now without jobs,” said Parul Koul, executive chair of the Alphabet Workers Union, in a statement. “This is egregious and unacceptable behavior by a company that made $17 billion dollars in profit last quarter alone.”

Alphabet said it would offer U.S.-based employees two months notice, plus 16 weeks of severance pay, along with two additional weeks for each year an employee being laid off from the nearly 25-year-old company has worked there. In other countries, the company will follow local processes and laws, which sometimes require consultations with employee representatives before workers are laid off.

The company will also offer former employees access to resources to help them with their immigration status, job placement and mental health, the spokesman said. Tech companies in the U.S. often have employees on work visas tied to their employment.

Write to Sam Schechner at Sam.Schechner@wsj.com and Miles Kruppa at miles.kruppa@wsj.com