diff --git a/src/Stache/Indexes/Terms/Associations.php b/src/Stache/Indexes/Terms/Associations.php
index 1ddef3781e3..606c2a674fb 100644
--- a/src/Stache/Indexes/Terms/Associations.php
+++ b/src/Stache/Indexes/Terms/Associations.php
@@ -8,6 +8,9 @@
 
 class Associations extends Index
 {
+    private ?array $grouped = null;
+    private ?array $groupedFrom = null;
+
     public function getItems()
     {
         return Taxonomy::findByHandle($handle = $this->store->childKey())
@@ -31,6 +34,86 @@ public function getItems()
             })->all();
     }
 
+    /**
+     * The associations for a term, found by its slug.
+     */
+    public function forSlug($slug): array
+    {
+        return $this->grouped()['slug'][(string) $slug] ?? [];
+    }
+
+    /**
+     * The associations for any of the given term slugs, in the order they are stored.
+     */
+    public function forSlugs(array $slugs): array
+    {
+        $associations = [];
+
+        foreach (array_unique(array_map('strval', $slugs)) as $slug) {
+            $associations += $this->forSlug($slug);
+        }
+
+        ksort($associations);
+
+        return $associations;
+    }
+
+    /**
+     * The associations for a term, found by the value entries store for it.
+     */
+    public function forValue($value): array
+    {
+        return $this->grouped()['value'][(string) $value] ?? [];
+    }
+
+    /**
+     * The slugs of the terms that entries in any of the given collections use.
+     */
+    public function slugsInCollections(array $collections): array
+    {
+        $slugs = [];
+
+        foreach ($collections as $collection) {
+            $slugs += $this->grouped()['collection'][(string) $collection] ?? [];
+        }
+
+        return array_map('strval', array_keys($slugs));
+    }
+
+    /**
+     * Every query for a term's entries, or for the terms a collection uses,
+     * would otherwise read through every association of the taxonomy. The
+     * associations are grouped once and looked up after that. The grouping
+     * is thrown away as soon as the associations are no longer the ones it
+     * was made from, however they came to change.
+     */
+    private function grouped(): array
+    {
+        $this->load();
+
+        if ($this->grouped !== null && $this->groupedFrom === $this->items) {
+            // Associations that are loaded again (between queued jobs, say) come back
+            // as a different array with the same contents. Holding on to that one
+            // means the next comparison is of an array with itself, which is instant,
+            // rather than of every association in it.
+            $this->groupedFrom = $this->items;
+
+            return $this->grouped;
+        }
+
+        $grouped = ['slug' => [], 'value' => [], 'collection' => []];
+
+        foreach ($this->items ?? [] as $i => $association) {
+            $grouped['slug'][(string) $association['slug']][$i] = $association;
+            $grouped['value'][(string) $association['value']][$i] = $association;
+            $grouped['collection'][(string) $association['collection']][(string) $association['slug']] = true;
+        }
+
+        $this->groupedFrom = $this->items;
+
+        return $this->grouped = $grouped;
+    }
+
     public function forgetEntry($id)
     {
         $this->items = $this->items()->reject(function ($association) use ($id) {
diff --git a/src/Stache/Query/QueriesTaxonomizedEntries.php b/src/Stache/Query/QueriesTaxonomizedEntries.php
index 8bfc66ce122..5299e958396 100644
--- a/src/Stache/Query/QueriesTaxonomizedEntries.php
+++ b/src/Stache/Query/QueriesTaxonomizedEntries.php
@@ -80,10 +80,9 @@ private function getKeysForTaxonomyWhereBasic($where)
 
         [$taxonomy, $slug] = explode('::', $term);
 
-        return Stache::store('terms')->store($taxonomy)
-            ->index('associations')
-            ->items()->where('slug', $slug)
-            ->pluck('entry');
+        return collect(Stache::store('terms')->store($taxonomy)->index('associations')->forSlug($slug))
+            ->pluck('entry')
+            ->values();
     }
 
     private function getKeysForTaxonomyWhereIn($where)
@@ -103,10 +102,9 @@ private function getKeysForTaxonomyWhereIn($where)
             });
 
         return $taxonomies->flatMap(function ($terms, $taxonomy) {
-            return Stache::store('terms')->store($taxonomy)
-                ->index('associations')
-                ->items()->whereIn('slug', $terms->all())
-                ->pluck('entry');
+            return collect(Stache::store('terms')->store($taxonomy)->index('associations')->forSlugs($terms->all()))
+                ->pluck('entry')
+                ->values();
         });
     }
 }
diff --git a/src/Stache/Query/TermQueryBuilder.php b/src/Stache/Query/TermQueryBuilder.php
index e02bdf86d2b..ea125c49912 100644
--- a/src/Stache/Query/TermQueryBuilder.php
+++ b/src/Stache/Query/TermQueryBuilder.php
@@ -152,12 +152,8 @@ public function get($columns = ['*'])
     private function filterUsagesWithinCollections($taxonomies)
     {
         $this->whereIn('id', collect($taxonomies)->flatMap(function ($taxonomy) {
-            return $this->store->store($taxonomy)
-                ->index('associations')
-                ->items()->whereIn('collection', $this->collections)
-                ->map(function ($item) use ($taxonomy) {
-                    return $taxonomy.'::'.$item['slug'];
-                });
+            return collect($this->store->store($taxonomy)->index('associations')->slugsInCollections($this->collections))
+                ->map(fn ($slug) => $taxonomy.'::'.$slug);
         })->all());
     }
 
diff --git a/src/Stache/Repositories/TermRepository.php b/src/Stache/Repositories/TermRepository.php
index b7069bd010b..5b16cb2095e 100644
--- a/src/Stache/Repositories/TermRepository.php
+++ b/src/Stache/Repositories/TermRepository.php
@@ -164,10 +164,9 @@ public function make(?string $slug = null): Term
 
     public function entriesCount(Term $term, ?string $status = null): int
     {
-        $items = $this->store->store($term->taxonomyHandle())
+        $items = collect($this->store->store($term->taxonomyHandle())
             ->index('associations')
-            ->items()
-            ->where('value', $term->inDefaultLocale()->slug());
+            ->forValue($term->inDefaultLocale()->slug()));
 
         if ($term instanceof LocalizedTerm) {
             $items = $items->where('site', $term->locale());
diff --git a/tests/Stache/Indexes/TermAssociationsTest.php b/tests/Stache/Indexes/TermAssociationsTest.php
new file mode 100644
index 00000000000..8d95dade986
--- /dev/null
+++ b/tests/Stache/Indexes/TermAssociationsTest.php
@@ -0,0 +1,138 @@
+<?php
+
+namespace Tests\Stache\Indexes;
+
+use Facades\Tests\Factories\EntryFactory;
+use PHPUnit\Framework\Attributes\Test;
+use Statamic\Facades\Collection;
+use Statamic\Facades\Entry;
+use Statamic\Facades\Stache;
+use Statamic\Facades\Taxonomy;
+use Statamic\Facades\Term;
+use Tests\PreventSavingStacheItemsToDisk;
+use Tests\TestCase;
+
+class TermAssociationsTest extends TestCase
+{
+    use PreventSavingStacheItemsToDisk;
+
+    private function associations()
+    {
+        return Stache::store('terms')->store('tags')->index('associations');
+    }
+
+    private function createEntries()
+    {
+        Taxonomy::make('tags')->save();
+        Collection::make('blog')->taxonomies(['tags'])->save();
+        Collection::make('news')->taxonomies(['tags'])->save();
+
+        EntryFactory::collection('blog')->id('1')->data(['tags' => ['Alfa', 'bravo']])->create();
+        EntryFactory::collection('blog')->id('2')->data(['tags' => ['bravo']])->create();
+        EntryFactory::collection('news')->id('3')->data(['tags' => ['Alfa', 'charlie']])->create();
+    }
+
+    #[Test]
+    public function it_finds_associations_by_slug_value_and_collection()
+    {
+        $this->createEntries();
+
+        $index = $this->associations();
+
+        $this->assertEquals(['1', '3'], collect($index->forSlug('alfa'))->pluck('entry')->sort()->values()->all());
+        $this->assertEquals(['1', '2'], collect($index->forSlug('bravo'))->pluck('entry')->sort()->values()->all());
+        $this->assertSame([], $index->forSlug('delta'));
+
+        // Entries store the value as it was typed; the slug is what a term is found by.
+        $this->assertEquals(['1', '3'], collect($index->forValue('Alfa'))->pluck('entry')->sort()->values()->all());
+        $this->assertSame([], $index->forValue('alfa'));
+
+        $this->assertEqualsCanonicalizing(['alfa', 'bravo'], $index->slugsInCollections(['blog']));
+        $this->assertEqualsCanonicalizing(['alfa', 'charlie'], $index->slugsInCollections(['news']));
+        $this->assertEqualsCanonicalizing(['alfa', 'bravo', 'charlie'], $index->slugsInCollections(['blog', 'news']));
+        $this->assertSame([], $index->slugsInCollections(['pages']));
+    }
+
+    #[Test]
+    public function associations_for_several_slugs_come_back_in_the_order_they_are_stored()
+    {
+        $this->createEntries();
+
+        $index = $this->associations();
+
+        $expected = $index->items()->whereIn('slug', ['charlie', 'alfa'])->all();
+
+        $this->assertSame($expected, $index->forSlugs(['charlie', 'alfa']));
+        $this->assertSame($expected, $index->forSlugs(['alfa', 'charlie', 'alfa']));
+        $this->assertSame(array_keys($expected), array_keys($index->forSlugs(['alfa', 'charlie'])));
+    }
+
+    #[Test]
+    public function it_gives_what_reading_through_every_association_gives()
+    {
+        $this->createEntries();
+
+        $index = $this->associations();
+
+        foreach (['alfa', 'bravo', 'charlie', 'delta'] as $slug) {
+            $this->assertSame($index->items()->where('slug', $slug)->all(), $index->forSlug($slug));
+        }
+
+        foreach (['Alfa', 'bravo', 'charlie', 'alfa'] as $value) {
+            $this->assertSame($index->items()->where('value', $value)->all(), $index->forValue($value));
+        }
+
+        foreach ([['blog'], ['news'], ['blog', 'news'], ['pages']] as $collections) {
+            $this->assertEqualsCanonicalizing(
+                $index->items()->whereIn('collection', $collections)->pluck('slug')->unique()->values()->all(),
+                $index->slugsInCollections($collections)
+            );
+        }
+    }
+
+    #[Test]
+    public function saving_entries_is_seen_straight_away()
+    {
+        $this->createEntries();
+
+        $index = $this->associations();
+        $this->assertCount(2, $index->forSlug('alfa'));
+        $this->assertSame([], $index->forSlug('delta'));
+
+        // A new entry using an existing term and a new one.
+        EntryFactory::collection('news')->id('4')->data(['tags' => ['alfa', 'delta']])->create();
+        $this->assertEquals(['1', '3', '4'], collect($index->forSlug('alfa'))->pluck('entry')->sort()->values()->all());
+        $this->assertEquals(['4'], collect($index->forSlug('delta'))->pluck('entry')->all());
+        $this->assertContains('delta', $index->slugsInCollections(['news']));
+
+        // An entry that stops using a term.
+        Entry::find('1')->set('tags', ['bravo'])->save();
+        $this->assertEquals(['3', '4'], collect($index->forSlug('alfa'))->pluck('entry')->sort()->values()->all());
+        $this->assertEqualsCanonicalizing(['bravo'], $index->slugsInCollections(['blog']));
+
+        // The queries built on the index agree.
+        $this->assertEquals(['3', '4'], Entry::query()->whereTaxonomy('tags::alfa')->get()->map->id()->sort()->values()->all());
+        $this->assertSame(2, Term::entriesCount(Term::find('tags::bravo')));
+        $this->assertEquals(['tags::bravo'], Term::query()->where('collection', 'blog')->get()->map->id()->all());
+    }
+
+    #[Test]
+    public function an_index_that_is_cleared_or_changed_directly_is_grouped_again()
+    {
+        $this->createEntries();
+
+        $index = $this->associations();
+        $this->assertCount(2, $index->forSlug('alfa'));
+
+        $index->push(['value' => 'alfa', 'slug' => 'alfa', 'entry' => '9', 'collection' => 'pages', 'site' => 'en']);
+        $this->assertCount(3, $index->forSlug('alfa'));
+        $this->assertSame(['alfa'], $index->slugsInCollections(['pages']));
+
+        $index->forgetEntry('9');
+        $this->assertCount(2, $index->forSlug('alfa'));
+        $this->assertSame([], $index->slugsInCollections(['pages']));
+
+        $index->clear();
+        $this->assertCount(2, $index->forSlug('alfa'));
+    }
+}