According to the Spanish newspaper El Mundo, the tax authorities suspect the company is not declaring some of its activities in the country.
The probe is related to the multinational’s VAT payments and taxes on income, the newspaper said.
The raids took place on Thursday in Google’s headquarters in Madrid and in a tech incubator run by the company.
A Google spokesperson said, "We comply with the tax law in Spain, as in every other country in which we operate.
“We are cooperating fully with the authorities in Madrid to answer their questions, as always.”
While the French authorities accused Google of owing €1.6bn (£1.22bn) in taxes, it is still unknown how much the investigators in Spain are seeking to recover.
A source told the Financial Times that Google had paid the “tiniest” amount of tax, despite making “billions” of euros in sales.
The company has been widely criticised around Europe for paying low taxes in recent years.
The European Commission said it was willing to investigate the deal should they receive a complaint.
In 2015, the British government introduced the so-called Google Tax, in an attempt to address the issue of global companies paying less than their perceived share of UK tax.