On-loan duo Jamie O'Hara and Will Hoskins netted their first goals for the club as Millwall eased out of the bottom four in style.
The home side enjoyed the better of the first half and took the lead through O'Hara's fine curled shot.
And the Lions made it 2-0 when Gary Alexander's left-footed volley was palmed by Cherries keeper Neil Moss straight to Hoskins who slotted home.
Lee Bradbury headed in for the visitors three minutes into stoppage time.
Millwall: Douglas, Senda, Robinson, Shaw, Frampton, Simpson (Harris 72), Brammer (Fuseini 37), O'Hara (Barron 78), Dunne, Alexander, Hoskins.
Subs Not Used: Day, Bakayogo.
Booked: Brammer, Robinson.
Goals: O'Hara 33, Hoskins 55.
Bournemouth: Moss, Telfer, Gowling, Wilson, Pearce (Lallana 62), Cooper, Anderton, Caracan, Hollands, Vokes (Kuffour 56), Bradbury, Lallana (McQuoid 85).
Subs Not Used: Stewart, Newman.
Goals: Bradbury 90.
Ref: Andy Hall (W Midlands).