There may be a number of factors why your boss isn't listening to you.
The first thing to do is evaluate the situation. Consider these questions:
- Are there times when your manager listens to you vs. times when s/he doesn't?
- Does it matter what topic or issue you're talking about?
- Does it make a difference if you are talking to your boss on a scheduled basis or "drop by" his/her office unannounced?
- Does your boss listen to others on your team, his/her boss or peers, or customers?
- Do you find that many others in your life don't listen to you or is it mainly just your boss?
While not an exhaustive list, answering these questions will give you some clues on how you may want to approach this situation. What you may discover is that there are certain circumstances that play into the problem you're experiencing. Some of it may be your own doing, your boss' doing, or a little bit of both.
Even if you skip the above (sometimes you need to respond in the moment as it's happening), the key thing you want to do is ask permission to share a concern you're having and/or schedule a time to talk to your boss in order to give him/her this feedback.
When you give your boss feedback about not listening to you, start with what you want. For example, "I want to make sure we're on the same page" or "I really enjoy working here and want to support you and the team as best I can."
Next, share your observations with your boss. For example, "When I was just talking right now I noticed that you seem distracted by your computer" or "The last couple times when we talked, I was interrupted by you before I could finish my thoughts" or "I'm not sure you're aware of this, but I've noticed that whenever I talk to you, you look down at your watch." Try to be as specific as you can, without blaming.
Next, share the impact that your boss' behavior of not listening is having on you. For example, "When we're having a meeting and you continue to work on your computer, it seems that you're not really listening or present." or "When you interrupt me, it feels disrespectful and that my opinion isn't valued." or "When you look at your watch, it makes me feel like you'd rather be somewhere else and what I have to say is not important."
Then give your boss some space to talk. You can do this by ending with a question. For example, "Would there be a better time to talk (when I can have your full attention)?" or Can you help me understand what's going on?" "Is there something I'm doing or saying when talking to you that makes you lose interest? I'd love to receive some constructive feedback."
Be sure to observe and listen for what your boss responds. Does s/he become defensive, look away, cut off the conversation, blame you, etc? Or does your boss thank you for the feedback, apologize for his/her behavior, and commit to listening better, suggesting some other options, or ask you for more clarity and try to understand where you're coming from?
This will help inform you on how to proceed from there. Hope that helps!