Magic Armor reduces damage taken from magical sources (spells).
Magic Armor follows the same formula for damage reduction as physical Armor; see Armor for the table and graph.
 Starting magic armor
Every hero starts with 5.50 Magic Armor, which is 24.8% magic damage reduction. This can be increased (and decreased) with skills and items.
 Items that increase magic armor
 Skills that increase magic armor
- Arachna's Harden Carapace - Dispels debuffs on self and increases magic armor by 5/10/18/35 for 3 seconds.
- Beardulon's Magic Resist (Level 4) - +8.2 Magic Armor. (Passive)
- Devourer's Cadaver Armor - +1/2/3/4 magic armor. Grants 1.5 strength when any hero dies within 400 radius of Devourer. (Passive)
- Magebane's Flash - Gives Magebane 3/6/10/15 magic armor and allies within 500 radius of target position 2/3/4/5 magic armor for 7 seconds.
 Items that reduce magic armor
- Harkon's Blade - When toggled on, attacks decrease magic armor by 5 for 6 seconds.
- Spellshards - Causes any magic damage dealt by holder to ignore 2/4/6 of the target's magic armor. (Will not cause magic armor to go below 0)
 Skills that reduce magic armor
- Blacksmith's Flaming Hammer - 15/20/25/30% Movement Slow, 10/20/30/40 Magic damage per second, -1/2/3/4 magic armor
- Hellbringer's Life Void - Applies Life Void to target for 5.5/7/8.5/10 seconds. -2.7/5.1/6.9/8.3 magic armor. 10/20/30/40% of the damage taken by target will heal the Hellbringer.
- Myrmidon's Wave Form - Applies Splashed to targets for 3 seconds. 15/25/35/45% Movement Slow, -1/-2/-3/-4 magic armor.