Bellatrix was an extremely powerful witch, second only to Lord Voldemort among the Death Eaters. She was an expert in the Dark Arts, an extremely skilled duellist, and an Occlumens. Her prodigious skill was proven by her many victories over other talented wizards and witches.
- Dark Arts Mastery: Bellatrix claimed to have been trained in the Dark Arts by Voldemort himself, and displayed a particular proficiency with, and affinity for, the Cruciatus Curse. She boasted to have knowledge of Dark spells that few could comprehend the power of; a claim supported by her status as Voldemort's "best lieutenant". Like her master, Bellatrix was known to cast the Killing Curse with particular skill and with no regard for the life she wished to extinguish.
- Non-verbal Magic: Bellatrix also seemed highly adept at using non-verbal spells. She slew a fox with a flash of green light on her way to Spinner's End in 1996 which was highly likely to have been a non-verbal Avada Kedavra. She also ferociously duelled Molly Weasley with such intensity that the floor around her became "hot and cracked" without mentioning a single incantation.
- Expert Duellist: Bellatrix defeated Aurors Nymphadora Tonks and Kingsley Shacklebolt in duels during the Battle of the Department of Mysteries, as well as her cousin Sirius, and was the only Death Eater to deflect a bolt from Albus Dumbledore himself, allowing her to escape the renowned wizard. She also quickly and single-handedly defeated four Snatchers and Fenrir Greyback, and later killed her niece in battle. Just before her death, Bellatrix duelled Hermione Granger, Luna Lovegood and Ginny Weasley all at once, and was described as being equal in power to all three of the talented, if inexperienced, witches. Her death at the hands of Molly Weasley was due to her greatly underestimating the witch, who was fuelled by grief over the murder of her son. In addition, despite her years of captivity within Azkaban, Bellatrix displayed incredible reflexes that outmatched the much younger and physically fit Harry Potter; she was able to conjure a Shield Charm and deflect his own spell back at him the moment he cast it. She was also physically fit enough to throw a knife across a room to strike her target and outrun Harry Potter with ease during the Attack on The Burrow given only a minimal head start. Bellatrix was also the last Death Eater standing (next to Voldemort) during the Battle of Hogwartsdespite being severely outnumbered by the Order of the Phoenix sympathizers, a testament to her amazing dueling ability.
- Occlumency/Legilimency Expert: Bellatrix trained her nephew Draco Malfoy in Occlumency as part of his mission to kill Albus Dumbledore, and thus was likely a Legilimens as well. Considering that Severus Snape was forced to use Legilimency in order to teach Harry Potter Occlumency, it is likely that Bellatrix needed to use the same power when teaching Draco.
- Unbreakable Vow Bonder: Bellatrix was capable of acting as a Bonder and initiating an Unbreakable Vow.