diff --git a/context/readerio/reader.go b/context/readerio/reader.go
index d57c958..8f8b6eb 100644
--- a/context/readerio/reader.go
+++ b/context/readerio/reader.go
@@ -65,3 +65,8 @@ func Defer[A any](gen L.Lazy[ReaderIO[A]]) ReaderIO[A] {
 func Memoize[A any](rdr ReaderIO[A]) ReaderIO[A] {
 	return R.Memoize[ReaderIO[A]](rdr)
 }
+
+// Flatten converts a nested [ReaderIO] into a [ReaderIO]
+func Flatten[A any](mma ReaderIO[ReaderIO[A]]) ReaderIO[A] {
+	return R.Flatten[ReaderIO[A]](mma)
+}
diff --git a/context/readerioeither/generic/reader.go b/context/readerioeither/generic/reader.go
index 2d18ace..4471b67 100644
--- a/context/readerioeither/generic/reader.go
+++ b/context/readerioeither/generic/reader.go
@@ -583,3 +583,12 @@ func Memoize[
 	A any](rdr GRA) GRA {
 	return RIE.Memoize[GRA](rdr)
 }
+
+func Flatten[
+	GGRA ~func(context.Context) GGIOA,
+	GGIOA ~func() E.Either[error, GRA],
+	GRA ~func(context.Context) GIOA,
+	GIOA ~func() E.Either[error, A],
+	A any](rdr GGRA) GRA {
+	return RIE.Flatten[GRA](rdr)
+}
diff --git a/context/readerioeither/reader.go b/context/readerioeither/reader.go
index 0d41094..a914c20 100644
--- a/context/readerioeither/reader.go
+++ b/context/readerioeither/reader.go
@@ -220,3 +220,9 @@ func Alt[A any](second L.Lazy[ReaderIOEither[A]]) func(ReaderIOEither[A]) Reader
 func Memoize[A any](rdr ReaderIOEither[A]) ReaderIOEither[A] {
 	return G.Memoize[ReaderIOEither[A]](rdr)
 }
+
+// Flatten converts a nested [ReaderIOEither] into a [ReaderIOEither]
+func Flatten[
+	A any](rdr ReaderIOEither[ReaderIOEither[A]]) ReaderIOEither[A] {
+	return G.Flatten[ReaderIOEither[ReaderIOEither[A]]](rdr)
+}
diff --git a/readerio/generic/reader.go b/readerio/generic/reader.go
index 8321dc2..2dc919f 100644
--- a/readerio/generic/reader.go
+++ b/readerio/generic/reader.go
@@ -124,3 +124,7 @@ func Memoize[GEA ~func(E) GA, GA ~func() A, E, A any](rdr GEA) GEA {
 		}
 	}
 }
+
+func Flatten[GEA ~func(R) GIOA, GGEA ~func(R) GIOEA, GIOA ~func() A, GIOEA ~func() GEA, R, A any](mma GGEA) GEA {
+	return MonadChain(mma, F.Identity[GEA])
+}
diff --git a/readerio/reader.go b/readerio/reader.go
index 10641da..9ac5e26 100644
--- a/readerio/reader.go
+++ b/readerio/reader.go
@@ -82,3 +82,7 @@ func Defer[E, A any](gen func() ReaderIO[E, A]) ReaderIO[E, A] {
 func Memoize[E, A any](rdr ReaderIO[E, A]) ReaderIO[E, A] {
 	return G.Memoize[ReaderIO[E, A]](rdr)
 }
+
+func Flatten[E, A any](mma ReaderIO[E, ReaderIO[E, A]]) ReaderIO[E, A] {
+	return G.Flatten[ReaderIO[E, A], ReaderIO[E, ReaderIO[E, A]]](mma)
+}