What is the difference between 哈哈, 呵呵, 嘻嘻, and 嘿嘿? Since you mentioned Wechat and QQ in the question, I'd say in a normal chat, there is no significant difference among 哈哈, 嘻嘻 and 嘿嘿 Normally when you chat online, your partner express his her happiness via these words Suragch gave a nice explanation of these words But 呵呵 is something different