It comes after the Scottish Government pledged £10million to help support low-income families provide food over the school holidays.
However, as the UK government has refused to fund free school meals in England, this money has been found from existing budgets rather than Barnett consequentials.
Now the Scottish Tories have been accused of false promises after Mr Ross previously pledged his party would support the policy.
Commenting, Stewart Stevenson MSP said:
“This was a key test of leadership for Douglas Ross and he has failed abysmally.
"The Scottish Tories are complete hypocrites for voting against free school meals despite previously claiming to support them. They are trying to hoodwink voters with false promises by saying one thing then doing the complete opposite when instructed by Boris Johnson.
"People in Scotland will not be fooled. By voting to deprive children of food, Scottish Tory MPs have also voted to deprive Scotland of crucial Barnett funding - leaving the SNP government to fund Scotland's progressive free school meals policy from existing budgets.
"The Scottish Tories are the same old toxic Westminster party. This month alone, they have voted to impose an extreme Brexit and a power grab on Scotland, and voted against free school meals, extending furlough support for jobs, and helping refugee children.
"The Scottish Government will continue to deliver progressive policies in Scotland despite Westminster cuts but the only way to properly protect Scotland's interests and values is to become an independent country."
"The Scottish Tories are complete hypocrites for voting against free school meals despite previously claiming to support them. They are trying to hoodwink voters with false promises by saying one thing then doing the complete opposite when instructed by Boris Johnson.
"People in Scotland will not be fooled. By voting to deprive children of food, Scottish Tory MPs have also voted to deprive Scotland of crucial Barnett funding - leaving the SNP government to fund Scotland's progressive free school meals policy from existing budgets.
"The Scottish Tories are the same old toxic Westminster party. This month alone, they have voted to impose an extreme Brexit and a power grab on Scotland, and voted against free school meals, extending furlough support for jobs, and helping refugee children.
"The Scottish Government will continue to deliver progressive policies in Scotland despite Westminster cuts but the only way to properly protect Scotland's interests and values is to become an independent country."