diff --git a/src/order-theory.lagda.md b/src/order-theory.lagda.md
index 5d93468b21..21d4f16a38 100644
--- a/src/order-theory.lagda.md
+++ b/src/order-theory.lagda.md
@@ -114,6 +114,8 @@ open import order-theory.reflective-galois-connections-large-posets public
 open import order-theory.resizing-posets public
 open import order-theory.resizing-preorders public
 open import order-theory.resizing-suplattices public
+open import order-theory.sequences-large-posets public
+open import order-theory.sequences-large-preorders public
 open import order-theory.similarity-of-elements-large-posets public
 open import order-theory.similarity-of-elements-large-preorders public
 open import order-theory.similarity-of-order-preserving-maps-large-posets public
diff --git a/src/order-theory/sequences-large-posets.lagda.md b/src/order-theory/sequences-large-posets.lagda.md
new file mode 100644
index 0000000000..a267f24a9f
--- /dev/null
+++ b/src/order-theory/sequences-large-posets.lagda.md
@@ -0,0 +1,89 @@
+# Sequences in large posets
+
+```agda
+module order-theory.sequences-large-posets where
+```
+
+<details><summary>Imports</summary>
+
+```agda
+open import elementary-number-theory.natural-numbers
+
+open import foundation.binary-relations
+open import foundation.constant-maps
+open import foundation.dependent-pair-types
+open import foundation.function-extensionality
+open import foundation.function-types
+open import foundation.large-binary-relations
+open import foundation.propositions
+open import foundation.sequences
+open import foundation.universe-levels
+
+open import order-theory.dependent-products-large-posets
+open import order-theory.large-posets
+```
+
+</details>
+
+## Idea
+
+A
+{{#concept "sequence" Disambiguation="in a large poset" Agda=type-sequence-Large-Poset}}
+in a [large poset](order-theory.large-posets.md) is a
+[sequence](foundation.sequences.md) in its underlying type.
+
+## Definitions
+
+### The large poset of sequences in large posets
+
+```agda
+module _
+  {α : Level → Level} {β : Level → Level → Level}
+  (P : Large-Poset α β)
+  where
+
+  sequence-Large-Poset : Large-Poset α β
+  sequence-Large-Poset = Π-Large-Poset (λ (n : ℕ) → P)
+
+  type-sequence-Large-Poset : (l : Level) → UU (α l)
+  type-sequence-Large-Poset =
+    type-Large-Poset sequence-Large-Poset
+
+  leq-prop-sequence-Large-Poset :
+    Large-Relation-Prop β type-sequence-Large-Poset
+  leq-prop-sequence-Large-Poset =
+    leq-prop-Large-Poset sequence-Large-Poset
+
+  leq-sequence-Large-Poset :
+    Large-Relation β type-sequence-Large-Poset
+  leq-sequence-Large-Poset =
+    leq-Large-Poset sequence-Large-Poset
+
+  is-prop-leq-sequence-Large-Poset :
+    is-prop-Large-Relation
+      ( type-sequence-Large-Poset)
+      ( leq-sequence-Large-Poset)
+  is-prop-leq-sequence-Large-Poset =
+    is-prop-leq-Large-Poset sequence-Large-Poset
+
+  refl-leq-sequence-Large-Poset :
+    is-reflexive-Large-Relation
+      ( type-sequence-Large-Poset)
+      ( leq-sequence-Large-Poset)
+  refl-leq-sequence-Large-Poset =
+    refl-leq-Large-Poset sequence-Large-Poset
+
+  transitive-leq-sequence-Large-Poset :
+    is-transitive-Large-Relation
+      ( type-sequence-Large-Poset)
+      ( leq-sequence-Large-Poset)
+  transitive-leq-sequence-Large-Poset =
+    transitive-leq-Large-Poset sequence-Large-Poset
+
+  antisymmetric-leq-sequence-Large-Poset :
+    is-antisymmetric-Large-Relation
+      ( type-sequence-Large-Poset)
+      ( leq-sequence-Large-Poset)
+  antisymmetric-leq-sequence-Large-Poset =
+    antisymmetric-leq-Large-Poset sequence-Large-Poset
+```
diff --git a/src/order-theory/sequences-large-preorders.lagda.md b/src/order-theory/sequences-large-preorders.lagda.md
new file mode 100644
index 0000000000..78f9dfe556
--- /dev/null
+++ b/src/order-theory/sequences-large-preorders.lagda.md
@@ -0,0 +1,82 @@
+# Sequences in large preorders
+
+```agda
+module order-theory.sequences-large-preorders where
+```
+
+<details><summary>Imports</summary>
+
+```agda
+open import elementary-number-theory.natural-numbers
+
+open import foundation.binary-relations
+open import foundation.constant-maps
+open import foundation.dependent-pair-types
+open import foundation.function-extensionality
+open import foundation.function-types
+open import foundation.large-binary-relations
+open import foundation.propositions
+open import foundation.sequences
+open import foundation.universe-levels
+
+open import order-theory.dependent-products-large-preorders
+open import order-theory.large-preorders
+```
+
+</details>
+
+## Idea
+
+A
+{{#concept "sequence" Disambiguation="in a large preorder" Agda=type-sequence-Large-Preorder}}
+in a [large preorder](order-theory.large-preorders.md) is a
+[sequence](foundation.sequences.md) in its underlying type.
+
+## Definitions
+
+### The large preorder of sequences in large preorders
+
+```agda
+module _
+  {α : Level → Level} {β : Level → Level → Level}
+  (P : Large-Preorder α β)
+  where
+
+  sequence-Large-Preorder : Large-Preorder α β
+  sequence-Large-Preorder = Π-Large-Preorder (λ (n : ℕ) → P)
+
+  type-sequence-Large-Preorder : (l : Level) → UU (α l)
+  type-sequence-Large-Preorder =
+    type-Large-Preorder sequence-Large-Preorder
+
+  leq-prop-sequence-Large-Preorder :
+    Large-Relation-Prop β type-sequence-Large-Preorder
+  leq-prop-sequence-Large-Preorder =
+    leq-prop-Large-Preorder sequence-Large-Preorder
+
+  leq-sequence-Large-Preorder :
+    Large-Relation β type-sequence-Large-Preorder
+  leq-sequence-Large-Preorder =
+    leq-Large-Preorder sequence-Large-Preorder
+
+  is-prop-leq-sequence-Large-Preorder :
+    is-prop-Large-Relation
+      ( type-sequence-Large-Preorder)
+      ( leq-sequence-Large-Preorder)
+  is-prop-leq-sequence-Large-Preorder =
+    is-prop-leq-Large-Preorder sequence-Large-Preorder
+
+  refl-leq-sequence-Large-Preorder :
+    is-reflexive-Large-Relation
+      ( type-sequence-Large-Preorder)
+      ( leq-sequence-Large-Preorder)
+  refl-leq-sequence-Large-Preorder =
+    refl-leq-Large-Preorder sequence-Large-Preorder
+
+  transitive-leq-sequence-Large-Preorder :
+    is-transitive-Large-Relation
+      ( type-sequence-Large-Preorder)
+      ( leq-sequence-Large-Preorder)
+  transitive-leq-sequence-Large-Preorder =
+    transitive-leq-Large-Preorder sequence-Large-Preorder
+```