The apology comes after the former Green Party leader wrote to 10 other female politicians opposed to a no-deal break with the EU, inviting them to form an "emergency cabinet".
She said the aim would be to secure a Commons vote of no-confidence in Boris Johnson followed by the formation of a government of national unity.
Ms Lucas, MP for Brighton Pavilion, has now apologised, saying it was "not right" to have only included white women in her proposal.
She said she will now do her "utmost to support, value and uplift women of colour working in politics".
In a post on Facebook, Ms Lucas said: "An all-white list of women isn't right.
"I should have reached out further and thought more deeply about who, and what kind of politics, an all-white list represents. I apologise."
Ms Lucas said she chose the people to reach out to in a bid to include all parties and parts of the UK in her plan to halt a no-deal.
She said: "I wanted the leadership/deputy leadership of all relevant parties in Westminster - three of the party leaders are women (which is the good news).
"I wanted two representatives from the main opposition party to represent the diverse views within it.
"Emily Thornberry is the shadow foreign secretary, who most often deputises for Jeremy Corbyn. Yvette Cooper has led cross-party parliamentary attempts to stop a No Deal Brexit from the backbenches."
Ms Lucas also said she wanted all parts of the UK to be "part of this conversation".
She added: "I realise that I did not get this right."
Ms Lucas admitted she was "wrong to overlook" her "women of colour colleagues" who share her political aims.
She said: "There are women of colour colleagues who are standing up to this Government's reckless gamble with Britain's future, and it was wrong to overlook them.
"I apologise to them and all who've been hurt by their exclusion. There are always lessons to be learnt, and I will do my utmost to support, value and uplift women of colour working in politics, particularly those with whom I share common ground."