Jade Yates shared the recording above on Facebook, to get her friends' opinions on the mysterious apparition.
"I won't be sleeping very well tonight," she wrote. "Who believes in ghosts? I didn't until about five mins ago."
Yates explained that the video showed her daughter Ruby sleeping in the front top left of the cot, in her room with the door shut, when nobody else was in the room.
"Well so I thought. You make up your own mind. One freaked out mumma right here," she added.
Rather than soothe the unsettled mother's fears, initial responses to the post claimed they could see not one, but two ghosts in the clip: "An old lady and a younger girl with a side fringe".
But others were more calming: "Jade this is awesome! Don't be scared, you will know if they aren't friendly, if they do keep you up at night you can ask them to leave," wrote one commenter.
"Otherwise your baby monitor could be getting vision of someone else's?"
Yates said she could see a baby older than her daughter who is able to sit up and an adult attending this baby and Ruby.
"Ruby was not unsettled at all," she added. "But she does wake every hour or so at night maybe this is why, someone wanting to play. I don't think they are nasty as the adult looks to be so attentive.
"I went in checked on her and she was fine, but when I came back to monitor they were gone, presuming I disturbed them, as I'd been watching them on the monitor for about 20 minutes."
Yates' video was viewed more than a million times, within 10 days of being shared on Saturday 23 January.
Yates then added a second clip showing baby monitor footage shot "moments before" the other clip.