Just because kittens look sweet, cuddly and innocent doesn't mean that they don't get annoyed every once in a while! However, growling in feline chat can mean a lot of different things, from fear to irritation and beyond. If you love your little one, learn to understand her language.
Annoyance
If your wee kitty growls at you, it could mean that she's irked by you. Perhaps she's sleepy and you keep petting her back. Growling might mean that she's had enough for the time being and just wants to be left alone. In kitty land, enough means enough! Don't overdo it. If your kitty growls or hisses at you, back off and try again later.
Warning
Growling in a kitten may also serve as a warning to unsuspecting newbies. For example, if you invite company over for lunch and your little fluff ball simply isn't in the mood to deal with anyone new, she may growl if a stranger approaches. When a kitten growls in this type of situation, it probably means something like "Don't even think about getting closer." You may also notice her tail aggressively swooshing about along with the growling -- yikes!
Defense
When a kitten growls, it could also mean that she's heading into defense mode. Maybe she's afraid that another pet in the household is going to attack her, for whatever reason. If you notice your kitten growling at your dog, for example, she may just naturally be protecting herself from what she perceives as being an upcoming canine attack.
Territorial
A kitten growling may be a territorial matter, especially if directed at another feline. Her growling may be her way of expressing to the other party, "This is my turf. Find your own place to hang out, because I'm not leaving any time soon." Cats often get agitated when another feline goes near where they eat, go to the bathroom or sleep.
Caution
Be very careful around kittens you don't know if they are growling at you. Even though kittens are tiny and delicate, they can use their claws and teeth to bite and scratch. This is especially dangerous if the kitten spends a lot of time outdoors. Leave a kitten be if her growling is directed at you. This way, you may be able to avoid infection and other possible dangers.