The choice of which phrase to use depends on the context and when you want to convey that you didn't know about something in the past. Here's a breakdown of the differences: "I have never heard of it before": This phrase is in the present perfect tense, which suggests that you are emphasizing your current state of knowledge. You are saying that up to this point in time (including the present), you have not heard of it. This phrase doesn't specify when you learned about it; it simply focuses on your current knowledge or lack thereof. "I never heard of it before": This phrase is in the simple past tense, indicating that in the past (before a specific point in time or event), you did not know about it. It doesn't address your current knowledge or when you might have learned about it; it solely references your past knowledge up to a particular point. "I had never heard of it before": This phrase is in the past perfect tense and is often used when discussing something in the past relative to another event in the past. It implies that, at a specific point in the past, you did not know about it. It establishes a past timeline and emphasizes that your lack of knowledge occurred before another event or action in the past. To choose the most appropriate phrase, consider the context and what you want to convey: If you simply want to express your current lack of knowledge without specifying when you learned about it, you can use "I have never heard of it before." If you want to emphasize that you didn't know about something in the past but don't need to link it to another past event, "I never heard of it before" is sufficient. If you want to establish a timeline of events and show that your lack of knowledge occurred before another event in the past, you can use "I had never heard of it before." Remember that the choice of tense can subtly change the emphasis and focus of your statement.