diff --git a/code/controllers/configuration/entries/general.dm b/code/controllers/configuration/entries/general.dm
index fabf4aa5cce..f805312d2b4 100644
--- a/code/controllers/configuration/entries/general.dm
+++ b/code/controllers/configuration/entries/general.dm
@@ -558,3 +558,6 @@
 /datum/config_entry/string/adminhelp_webhook_pfp
 
 /datum/config_entry/string/adminhelp_webhook_name
+
+/datum/config_entry/flag/cache_assets
+	default = TRUE
diff --git a/code/controllers/subsystem/assets.dm b/code/controllers/subsystem/assets.dm
index ef79e55dbe5..56314c74963 100644
--- a/code/controllers/subsystem/assets.dm
+++ b/code/controllers/subsystem/assets.dm
@@ -2,7 +2,7 @@ SUBSYSTEM_DEF(assets)
 	name = "Assets"
 	init_order = INIT_ORDER_ASSETS
 	flags = SS_NO_FIRE
-	var/list/cache = list()
+	var/list/datum/asset_cache_item/cache = list()
 	var/list/preload = list()
 	var/datum/asset_transport/transport = new()
 
diff --git a/code/modules/asset_cache/asset_list.dm b/code/modules/asset_cache/asset_list.dm
index de2bf531544..372207fe1b5 100644
--- a/code/modules/asset_cache/asset_list.dm
+++ b/code/modules/asset_cache/asset_list.dm
@@ -1,3 +1,4 @@
+#define ASSET_CROSS_ROUND_CACHE_DIRECTORY "tmp/assets"
 
 //These datums are used to populate the asset cache, the proc "register()" does this.
 //Place any asset datums you create in asset_list_items.dm
@@ -16,6 +17,11 @@ GLOBAL_LIST_EMPTY(asset_datums)
 	/// Whether or not this asset should be loaded in the "early assets" SS
 	var/early = FALSE
 
+	/// Whether or not this asset can be cached across rounds of the same commit under the `CACHE_ASSETS` config.
+	/// This is not a *guarantee* the asset will be cached. Not all asset subtypes respect this field, and the
+	/// config can, of course, be disabled.
+	var/cross_round_cachable = FALSE
+
 /datum/asset/New()
 	GLOB.asset_datums[type] = src
 	register()
@@ -36,6 +42,9 @@ GLOBAL_LIST_EMPTY(asset_datums)
 /datum/asset/proc/send(client)
 	return
 
+/// Returns whether or not the asset should attempt to read from cache
+/datum/asset/proc/should_refresh()
+	return !cross_round_cachable || !CONFIG_GET(flag/cache_assets)
 
 /// If you don't need anything complicated.
 /datum/asset/simple
@@ -105,10 +114,33 @@ GLOBAL_LIST_EMPTY(asset_datums)
 	var/name
 	var/list/sizes = list()    // "32x32" -> list(10, icon/normal, icon/stripped)
 	var/list/sprites = list()  // "foo_bar" -> list("32x32", 5)
+	var/list/cached_spritesheets_needed
+	var/generating_cache = FALSE
+
+/datum/asset/spritesheet/should_refresh()
+	if (..())
+		return TRUE
+
+	// Static so that the result is the same, even when the files are created, for this run
+	var/static/should_refresh = null
+
+	if (isnull(should_refresh))
+		// `fexists` seems to always fail on static-time
+		should_refresh = !fexists("[ASSET_CROSS_ROUND_CACHE_DIRECTORY]/spritesheet.[name].css")
+
+	return should_refresh
 
 /datum/asset/spritesheet/register()
+	SHOULD_NOT_OVERRIDE(TRUE)
+
 	if (!name)
 		CRASH("spritesheet [type] cannot register without a name")
+
+	if (!should_refresh() && read_from_cache())
+		return
+
+	create_spritesheets()
+
 	ensure_stripped()
 	for(var/size_id in sizes)
 		var/size = sizes[size_id]
@@ -120,23 +152,32 @@ GLOBAL_LIST_EMPTY(asset_datums)
 	SSassets.transport.register_asset(res_name, fcopy_rsc(fname))
 	fdel(fname)
 
-/datum/asset/spritesheet/send(client/C)
+	if (CONFIG_GET(flag/cache_assets) && cross_round_cachable)
+		write_to_cache()
+
+/datum/asset/spritesheet/send(client/client)
 	if (!name)
 		return
+
+	if (!should_refresh())
+		return send_from_cache(client)
+
 	var/all = list("spritesheet_[name].css")
 	for(var/size_id in sizes)
 		all += "[name]_[size_id].png"
-	. = SSassets.transport.send_assets(C, all)
+	. = SSassets.transport.send_assets(client, all)
 
 /datum/asset/spritesheet/get_url_mappings()
 	if (!name)
 		return
+
+	if (!should_refresh())
+		return get_cached_url_mappings()
+
 	. = list("spritesheet_[name].css" = SSassets.transport.get_asset_url("spritesheet_[name].css"))
 	for(var/size_id in sizes)
 		.["[name]_[size_id].png"] = SSassets.transport.get_asset_url("[name]_[size_id].png")
 
-
-
 /datum/asset/spritesheet/proc/ensure_stripped(sizes_to_strip = sizes)
 	for(var/size_id in sizes_to_strip)
 		var/size = sizes[size_id]
@@ -158,7 +199,7 @@ GLOBAL_LIST_EMPTY(asset_datums)
 	for (var/size_id in sizes)
 		var/size = sizes[size_id]
 		var/icon/tiny = size[SPRSZ_ICON]
-		out += ".[name][size_id]{display:inline-block;width:[tiny.Width()]px;height:[tiny.Height()]px;background:url('[SSassets.transport.get_asset_url("[name]_[size_id].png")]') no-repeat;}"
+		out += ".[name][size_id]{display:inline-block;width:[tiny.Width()]px;height:[tiny.Height()]px;background:url('[get_background_url("[name]_[size_id].png")]') no-repeat;}"
 
 	for (var/sprite_id in sprites)
 		var/sprite = sprites[sprite_id]
@@ -176,6 +217,64 @@ GLOBAL_LIST_EMPTY(asset_datums)
 
 	return out.Join("\n")
 
+/datum/asset/spritesheet/proc/read_from_cache()
+	var/replaced_css = file2text("[ASSET_CROSS_ROUND_CACHE_DIRECTORY]/spritesheet.[name].css")
+
+	var/regex/find_background_urls = regex(@"background:url\('%(.+?)%'\)", "g")
+	while (find_background_urls.Find(replaced_css))
+		var/asset_id = find_background_urls.group[1]
+		var/asset_cache_item = SSassets.transport.register_asset(asset_id, "[ASSET_CROSS_ROUND_CACHE_DIRECTORY]/spritesheet.[asset_id]")
+		var/asset_url = SSassets.transport.get_asset_url(asset_cache_item = asset_cache_item)
+		replaced_css = replacetext(replaced_css, find_background_urls.match, "background:url('[asset_url]')")
+		LAZYADD(cached_spritesheets_needed, asset_id)
+
+	var/replaced_css_filename = "data/spritesheets/spritesheet_[name].css"
+	rustg_file_write(replaced_css, replaced_css_filename)
+	SSassets.transport.register_asset("spritesheet_[name].css", replaced_css_filename)
+
+	fdel(replaced_css_filename)
+
+	return TRUE
+
+/datum/asset/spritesheet/proc/send_from_cache(client/client)
+	if (isnull(cached_spritesheets_needed))
+		stack_trace("cached_spritesheets_needed was null when sending assets from [type] from cache")
+		cached_spritesheets_needed = list()
+
+	return SSassets.transport.send_assets(client, cached_spritesheets_needed + "spritesheet_[name].css")
+
+/// Returns the URL to put in the background:url of the CSS asset
+/datum/asset/spritesheet/proc/get_background_url(asset)
+	if (generating_cache)
+		return "%[asset]%"
+	else
+		return SSassets.transport.get_asset_url(asset)
+
+/datum/asset/spritesheet/proc/write_to_cache()
+	for (var/size_id in sizes)
+		fcopy(SSassets.cache["[name]_[size_id].png"].resource, "[ASSET_CROSS_ROUND_CACHE_DIRECTORY]/spritesheet.[name]_[size_id].png")
+
+	generating_cache = TRUE
+	var/mock_css = generate_css()
+	generating_cache = FALSE
+
+	rustg_file_write(mock_css, "[ASSET_CROSS_ROUND_CACHE_DIRECTORY]/spritesheet.[name].css")
+
+/datum/asset/spritesheet/proc/get_cached_url_mappings()
+	var/list/mappings = list()
+	mappings["spritesheet_[name].css"] = SSassets.transport.get_asset_url("spritesheet_[name].css")
+
+	for (var/asset_name in cached_spritesheets_needed)
+		mappings[asset_name] = SSassets.transport.get_asset_url(asset_name)
+
+	return mappings
+
+/// Override this in order to start the creation of the spritehseet.
+/// This is where all your Insert, InsertAll, etc calls should be inside.
+/datum/asset/spritesheet/proc/create_spritesheets()
+	SHOULD_CALL_PARENT(FALSE)
+	CRASH("create_spritesheets() not implemented for [type]!")
+
 /datum/asset/spritesheet/proc/Insert(sprite_name, icon/I, icon_state="", dir=SOUTH, frame=1, moving=FALSE)
 	I = icon(I, icon_state=icon_state, dir=dir, frame=frame, moving=moving)
 	if (!I || !length(icon_states(I)))  // that direction or state doesn't exist
@@ -281,10 +380,9 @@ GLOBAL_LIST_EMPTY(asset_datums)
 	_abstract = /datum/asset/spritesheet/simple
 	var/list/assets
 
-/datum/asset/spritesheet/simple/register()
+/datum/asset/spritesheet/simple/create_spritesheets()
 	for (var/key in assets)
 		Insert(key, assets[key])
-	..()
 
 //Generates assets based on iconstates of a single icon
 /datum/asset/simple/icon_states
@@ -393,3 +491,5 @@ GLOBAL_LIST_EMPTY(asset_datums)
 /datum/asset/json/proc/generate()
 	SHOULD_CALL_PARENT(FALSE)
 	CRASH("generate() not implemented for [type]!")
+
+#undef ASSET_CROSS_ROUND_CACHE_DIRECTORY
diff --git a/code/modules/asset_cache/asset_list_items.dm b/code/modules/asset_cache/asset_list_items.dm
index 4b1543a3fdd..eac432b21da 100644
--- a/code/modules/asset_cache/asset_list_items.dm
+++ b/code/modules/asset_cache/asset_list_items.dm
@@ -153,7 +153,7 @@
 /datum/asset/spritesheet/chat
 	name = "chat"
 
-/datum/asset/spritesheet/chat/register()
+/datum/asset/spritesheet/chat/create_spritesheets()
 	InsertAll("emoji", EMOJI_SET)
 	// pre-loading all lanugage icons also helps to avoid meta
 	InsertAll("language", 'icons/misc/language.dmi')
@@ -164,7 +164,6 @@
 		if (icon != 'icons/misc/language.dmi')
 			var/icon_state = initial(L.icon_state)
 			Insert("language-[icon_state]", icon, icon_state=icon_state)
-	..()
 
 /datum/asset/simple/lobby
 	assets = list(
@@ -208,9 +207,8 @@
 /datum/asset/spritesheet/simple/achievements
 	name ="achievements"
 
-/datum/asset/spritesheet/simple/achievements/register()
+/datum/asset/spritesheet/simple/achievements/create_spritesheets()
 	InsertAll("", ACHIEVEMENTS_SET)
-	return ..()
 
 /datum/asset/spritesheet/simple/pills
 	name = "pills"
@@ -270,15 +268,14 @@
 /datum/asset/spritesheet/pipes
 	name = "pipes"
 
-/datum/asset/spritesheet/pipes/register()
+/datum/asset/spritesheet/pipes/create_spritesheets()
 	for (var/each in list('icons/obj/atmospherics/pipes/pipe_item.dmi', 'icons/obj/atmospherics/pipes/disposal.dmi', 'icons/obj/atmospherics/pipes/transit_tube.dmi', 'icons/obj/plumbing/fluid_ducts.dmi'))
 		InsertAll("", each, GLOB.alldirs)
-	..()
 
 /datum/asset/spritesheet/supplypods
 	name = "supplypods"
 
-/datum/asset/spritesheet/supplypods/register()
+/datum/asset/spritesheet/supplypods/create_spritesheets()
 	for (var/style in 1 to length(GLOB.podstyles))
 		if (style == STYLE_SEETHROUGH)
 			Insert("pod_asset[style]", icon('icons/obj/supplypods.dmi' , "seethrough-icon"))
@@ -302,13 +299,12 @@
 				glow = "pod_glow_[glow]"
 				podIcon.Blend(icon('icons/obj/supplypods.dmi', glow), ICON_OVERLAY)
 		Insert("pod_asset[style]", podIcon)
-	return ..()
 
 // Representative icons for each research design
 /datum/asset/spritesheet/research_designs
 	name = "design"
 
-/datum/asset/spritesheet/research_designs/register()
+/datum/asset/spritesheet/research_designs/create_spritesheets()
 	for (var/path in subtypesof(/datum/design))
 		var/datum/design/D = path
 
@@ -367,12 +363,11 @@
 					I.Blend(icon(icon_file, keyboard, SOUTH), ICON_OVERLAY)
 
 		Insert(initial(D.id), I)
-	return ..()
 
 /datum/asset/spritesheet/vending
 	name = "vending"
 
-/datum/asset/spritesheet/vending/register()
+/datum/asset/spritesheet/vending/create_spritesheets()
 	for (var/k in GLOB.vending_products)
 		var/atom/item = k
 		if (!ispath(item, /atom))
@@ -405,7 +400,6 @@
 		var/imgid = replacetext(replacetext("[item]", "/obj/item/", ""), "/", "-")
 
 		Insert(imgid, I)
-	return ..()
 
 /datum/asset/simple/genetics
 	assets = list(
@@ -427,19 +421,17 @@
 /datum/asset/spritesheet/sheetmaterials
 	name = "sheetmaterials"
 
-/datum/asset/spritesheet/sheetmaterials/register()
+/datum/asset/spritesheet/sheetmaterials/create_spritesheets()
 	InsertAll("", 'icons/obj/stack_objects.dmi')
 
 	// Special case to handle Bluespace Crystals
 	Insert("polycrystal", 'icons/obj/telescience.dmi', "polycrystal")
-	..()
 
 /datum/asset/spritesheet/mafia
 	name = "mafia"
 
-/datum/asset/spritesheet/mafia/register()
+/datum/asset/spritesheet/mafia/create_spritesheets()
 	InsertAll("", 'icons/obj/mafia.dmi')
-	..()
 
 /datum/asset/simple/portraits
 	assets = list()
@@ -470,7 +462,7 @@
 /datum/asset/spritesheet/fish
 	name = "fish"
 
-/datum/asset/spritesheet/fish/register()
+/datum/asset/spritesheet/fish/create_spritesheets()
 	for (var/path in subtypesof(/datum/aquarium_behaviour/fish))
 		var/datum/aquarium_behaviour/fish/fish_type = path
 		var/fish_icon = initial(fish_type.icon)
@@ -479,7 +471,6 @@
 		if(sprites[id]) //no dupes
 			continue
 		Insert(id, fish_icon, fish_icon_state)
-	..()
 
 /datum/asset/simple/adventure
 	assets = list(
@@ -524,12 +515,11 @@
 	name = "moods"
 	var/iconinserted = 1
 
-/datum/asset/spritesheet/moods/register()
+/datum/asset/spritesheet/moods/create_spritesheets()
 	for(var/i in 1 to 9)
 		var/target_to_insert = "mood"+"[iconinserted]"
 		Insert(target_to_insert, 'icons/hud/screen_gen.dmi', target_to_insert)
 		iconinserted++
-	..()
 
 /datum/asset/spritesheet/moods/ModifyInserted(icon/pre_asset)
 	var/blended_color
diff --git a/code/modules/client/preferences/assets.dm b/code/modules/client/preferences/assets.dm
index 88d4313cae7..de29b6e4fbd 100644
--- a/code/modules/client/preferences/assets.dm
+++ b/code/modules/client/preferences/assets.dm
@@ -2,8 +2,9 @@
 /datum/asset/spritesheet/preferences
 	name = "preferences"
 	early = TRUE
+	cross_round_cachable = TRUE
 
-/datum/asset/spritesheet/preferences/register()
+/datum/asset/spritesheet/preferences/create_spritesheets()
 	var/list/to_insert = list()
 
 	for (var/preference_key in GLOB.preference_entries_by_key)
@@ -36,8 +37,6 @@
 		var/list/inserting = to_insert[spritesheet_key]
 		Insert(spritesheet_key, inserting[1], inserting[2])
 
-	return ..()
-
 /// Returns the key that will be used in the spritesheet for a given value.
 /datum/preference/proc/get_spritesheet_key(value)
 	return "[savefile_key]___[sanitize_css_class_name(value)]"
diff --git a/code/modules/client/preferences/middleware/antags.dm b/code/modules/client/preferences/middleware/antags.dm
index 37a0f7eb471..b782397fd5b 100644
--- a/code/modules/client/preferences/middleware/antags.dm
+++ b/code/modules/client/preferences/middleware/antags.dm
@@ -108,8 +108,9 @@
 /datum/asset/spritesheet/antagonists
 	name = "antagonists"
 	early = TRUE
+	cross_round_cachable = TRUE
 
-/datum/asset/spritesheet/antagonists/register()
+/datum/asset/spritesheet/antagonists/create_spritesheets()
 	// Antagonists that don't have a dynamic ruleset, but do have a preference
 	var/static/list/non_ruleset_antagonists = list(
 		ROLE_FUGITIVE = /datum/antagonist/fugitive,
@@ -156,8 +157,6 @@
 	for (var/spritesheet_key in to_insert)
 		Insert(spritesheet_key, to_insert[spritesheet_key])
 
-	return ..()
-
 /// Serializes an antag name to be used for preferences UI
 /proc/serialize_antag_name(antag_name)
 	// These are sent through CSS, so they need to be safe to use as class names.
diff --git a/code/modules/client/preferences/middleware/species.dm b/code/modules/client/preferences/middleware/species.dm
index c6017d9f393..02efe1e223a 100644
--- a/code/modules/client/preferences/middleware/species.dm
+++ b/code/modules/client/preferences/middleware/species.dm
@@ -9,8 +9,9 @@
 /datum/asset/spritesheet/species
 	name = "species"
 	early = TRUE
+	cross_round_cachable = TRUE
 
-/datum/asset/spritesheet/species/register()
+/datum/asset/spritesheet/species/create_spritesheets()
 	var/list/to_insert = list()
 
 	for (var/species_id in get_selectable_species())
@@ -32,5 +33,3 @@
 
 	for (var/spritesheet_key in to_insert)
 		Insert(spritesheet_key, to_insert[spritesheet_key])
-
-	return ..()
diff --git a/config/config.txt b/config/config.txt
index ea51ed77042..3e36f266db8 100644
--- a/config/config.txt
+++ b/config/config.txt
@@ -583,3 +583,10 @@ URGENT_AHELP_COOLDOWN 300
 ## Based on config directory, so "motd.txt" points to "config/motd.txt"
 MOTD motd.txt
 #MOTD motd_extra.txt
+
+## Assets can opt-in to caching their results into `tmp`.
+## This is important, as preferences assets take upwards of 30 seconds (without sleeps) to collect.
+## The cache is assumed to be cleared by TGS recompiling, which deletes `tmp`.
+## This should be disabled (through `CACHE_ASSETS 0`) on development,
+## but enabled on production (the default).
+CACHE_ASSETS 0