Tom and Gatsby first meet at one of Gatsby's lavish parties, where they exchange a few polite words. Tom is immediately suspicious of Gatsby and his wealth, while Gatsby is courteous but reserved. This meeting reveals that Tom has an instinctive mistrust of Gatsby and his mysterious background, while Gatsby appears to be aware of the social divide between them. Furthermore, it suggests that despite their polite conversation, there is an underlying tension between them that will eventually come to the surface as the story progresses.