Games like Galactic Defense: Automation
Games like Galactic Defense: Automation include Mindustry, Ratropolis, Stronghold: Definitive Edition, Bloons TD 6, and Creeper World 4. We matched them by the tags players give Galactic Defense: Automation on Steam (Strategy, RTS, Tower Defense, Real Time Tactics, and Roguelite): closest matches first, and among equally close ones the better-known games.

Mindustry
Shared: Tower Defense · RTS · Strategy

Ratropolis
Shared: Strategy · 2D · Roguelite

Stronghold: Definitive Edition
Shared: Strategy · Real Time Tactics · RTS

Bloons TD 6
Shared: Strategy · Tower Defense · Singleplayer

Creeper World 4
Shared: Tower Defense · Real Time Tactics · RTS

Battlefleet Gothic: Armada 2
Shared: Strategy · RTS · Real Time Tactics

Plants vs. Zombies GOTY Edition
Shared: Strategy · Tower Defense · 2D

Yokai Art: Night Parade of One Hundred Demons
Shared: Strategy · Tower Defense · Roguelite

Broken Arrow
Shared: Strategy · RTS · Real Time Tactics

Call to Arms - Gates of Hell: Ostfront
Shared: Strategy · Real Time Tactics · RTS

Stronghold Crusader: Definitive Edition
Shared: Strategy · Real Time Tactics · Tower Defense

Planetary Annihilation: TITANS
Shared: Strategy · RTS · Real Time Tactics

Tower Dominion
Shared: Strategy · Tower Defense · RTS

Aliens: Dark Descent
Shared: Strategy · RTS · Real Time Tactics

Total War: WARHAMMER III
Shared: Strategy · RTS · Real Time Tactics

Tower Factory
Shared: Strategy · Tower Defense · RTS

STAR WARS™ Empire at War - Gold Pack
Shared: Strategy · RTS · Space

Shadow Tactics: Blades of the Shogun
Shared: Strategy · Real Time Tactics · Isometric

Creeper World 3: Arc Eternal
Shared: Strategy · Tower Defense · RTS

The King is Watching
Shared: Tower Defense · RTS · Strategy

Stronghold HD (2012)
Shared: Real Time Tactics · Tower Defense · RTS

Men of War: Assault Squad 2
Shared: Strategy · RTS · Real Time Tactics

Total War: WARHAMMER II
Shared: Strategy · RTS · Real Time Tactics

Starship Troopers: Terran Command
Shared: Strategy · RTS · Tower Defense