Attack is a card type. An Attack is typically a card that is likely to somehow hurt the opponents of the player who plays it—either by reducing the range of options available to them on an upcoming turn, or by weakening their overall deck composition. All Attack cards are Action cards.
Attacks are often a crucial component of an engine strategy: an engine deck can take longer to build than an unimpeded Big Money deck; but an engine that frequently plays Attack cards can slow down an opponent's deck-building enough to make engine construction competitive. However, since they attack the opponent, strong Attack cards often have relatively weak (or even no) direct benefits to their owner's deck, slowing down deck-building from that direction as well.
Not every play of every Attack card will adversely affect (or even affect at all) an opponent; and some cards which can be used to hurt an opponent, such as Masquerade and Ill-Gotten Gains, are not Attacks. The fact that "Attack" is a card type becomes relevant in that certain cards have specified interactions with Attacks. Most of these are Reaction cards that can be revealed when an opponent plays an Attack to have some effect that usually mitigates or counters the adverse effect of the Attack.
All Dominion expansions have at least two Attack cards. The greatest density of Attack cards is found in Cornucopia, which contains three Attack cards out of 13 Kingdom cards plus Followers, an Attack–Prize. The lowest density of Attack cards is in Prosperity and Hinterlands, which have only three Attacks out of 25 and 26 Kingdom cards respectively. In Hinterlands, the non-Attack curser Ill-Gotten Gains takes the place of an Attack card; in Prosperity, Donald X. Vaccarino deliberately kept the number of Attacks low in order to make it easier to construct decks that can buy Colony, and to compensate, Prosperity has a large number of non-Attack interactive cards.
 Kinds of Attacks
 Handsize attacks
Handsize attacks reduce the number of cards you have in hand on your next turn, thus reducing the range of options available to you on that turn. The majority of these make you discard down to 3 cards, and the victim chooses which cards to discard; thus multiple plays of such handsize attacks don't hurt the victim more than the first one. These include Militia, Ghost Ship, Goons, Margrave, Mercenary, Followers, and Sir Michael. Urchin makes you discard down to 4 cards. Minion is a variation that makes you discard down to 4 cards, but you can't choose which card to discard, because you discard your whole hand and draw 4 new ones. Pillage is a one-shot where the attacker chooses the card to discard; and Taxman forces everyone to discard a particular Treasure. Some handsize attacks can make victims continue discarding cards on multiple plays: Torturer stacks if the victim does not wish to gain a Curse; Cutpurse and Bureaucrat target Coppers and Victory cards respectively and on repeated plays can continue reducing your handsize as long as you have the targeted cards in your hand.
The strongest counters to most handsize attacks include Menagerie, which is more likely to grant +3 cards in smaller hands, and Horse Traders, which increases your handsize again once your next turn starts.
 Attacks that trash your cards
Trashing attacks usually trash one of the top two cards of the opponents' decks, directly combating their deck-building efforts. Donald X. Vaccarino has described it as challenging to create trashing attacks that aren't too random in their degree of effectiveness and don't totally ruin players' enjoyment of the game. This is accomplished in various ways: trashing can be restricted to Treasure cards (as in Thief, Noble Brigand, Pirate Ship) or to a certain price range (Knights and Rogue), or the Attack can offer the victim a replacement for the trashed card (Saboteur and Swindler).
 Attacks that give you junk
Attacks that add undesirable cards to opponents' decks hurt an opponent by weakening the turns on which they draw those "junk" cards, and by slowing their deck cycling. The majority of these distribute Curse cards and therefore are referred to as cursers; these include Witch, Torturer, Sea Hag, Familiar, Mountebank, Young Witch, Followers, and Soothsayer; the on-gain effect of Ill-Gotten Gains has the same function as these Attacks, though it is not itself an Attack card. Dark Ages does not contain cursers; instead, its junking attacks are Looters which distribute Ruins: Marauder and Cultist. Noble Brigand sometimes distributes Copper. A few junking attacks can distribute a variety of junk cards, including Curses under some circumstances: Ambassador, Swindler and Jester.
 Attacks that muck with your deck order
These attacks attempt to ensure that weak cards are left on top of an opponent's deck, or strong cards are discarded, weakening their upcoming hands and denying them opportunities to play their best cards. Bureaucrat, Sea Hag, and Fortune Teller specifically put bad cards on the opponent's deck; Spy, Scrying Pool, Rabble, Oracle can make them discard whatever good cards are there while leaving bad cards behind.
 List of Attack cards sorted by expansion
- Dominion: Bureaucrat, Militia, Spy, Thief, Witch
- Intrigue: Swindler, Minion, Saboteur, Torturer
- Seaside: Ambassador, Cutpurse, Pirate Ship, Sea Hag, Ghost Ship
- Alchemy: Scrying Pool, Familiar
- Prosperity: Mountebank, Rabble, Goons
- Cornucopia: Fortune Teller, Young Witch, Jester, Followers
- Hinterlands: Oracle, Noble Brigand, Margrave
- Dark Ages: Urchin, Mercenary, Marauder, Cultist, Knights, Pillage, Rogue
- Guilds: Taxman, Soothsayer