On a computer, open the exact message you want to answer and check its To and Cc lines. If there are other recipients to include, look for Reply all for that message. Check the recipient list in the draft before sending.
01Open the message that has the recipients
Section linkIn Conversation View, Gmail puts the latest email at the bottom. Expand the earlier message if it went to a different group. For example, if the original email copied the project team and the latest follow-up was sent only to you, use the original message when you need to answer the project team.
02Compare Reply and Reply all
Section linkReply targets the sender. Reply all also includes the recipients on that message’s To and Cc lines. If the sender was writing just to you, there may be no wider group for Gmail to include. Open the reply draft and inspect the recipient list. Add any missing person only after you confirm they should see the message and its quoted thread.
03Check the default or separate the thread
Section linkOpen Settings → See all settings → General and look for Default reply behavior if the buttons appear in an unexpected order. To inspect one message at a time, go to Conversation View in settings, turn it off and save. Reopen the specific email, choose the intended reply option and check the recipients again.