diff --git a/internal/lang/eval.go b/internal/lang/eval.go
index c1faca9e6..fe5fc1b76 100644
--- a/internal/lang/eval.go
+++ b/internal/lang/eval.go
@@ -296,7 +296,7 @@ func (s *Scope) evalContext(refs []*addrs.Reference, selfAddr addrs.Referenceabl
 					// this codepath doesn't really "know about". If the "self"
 					// object starts being supported in more contexts later then
 					// we'll need to adjust this message.
-					Detail:  `The "self" object is not available in this context. This object can be used only in resource provisioner and connection blocks.`,
+					Detail:  `The "self" object is not available in this context. This object can be used only in resource provisioner, connection, and postcondition blocks.`,
 					Subject: ref.SourceRange.ToHCL().Ptr(),
 				})
 				continue
diff --git a/internal/terraform/evaluate_valid.go b/internal/terraform/evaluate_valid.go
index 232f6913d..1d43cc4fc 100644
--- a/internal/terraform/evaluate_valid.go
+++ b/internal/terraform/evaluate_valid.go
@@ -58,7 +58,7 @@ func (d *evaluationStateData) staticValidateReference(ref *addrs.Reference, self
 				// this codepath doesn't really "know about". If the "self"
 				// object starts being supported in more contexts later then
 				// we'll need to adjust this message.
-				Detail:  `The "self" object is not available in this context. This object can be used only in resource provisioner and connection blocks.`,
+				Detail:  `The "self" object is not available in this context. This object can be used only in resource provisioner, connection, and postcondition blocks.`,
 				Subject: ref.SourceRange.ToHCL().Ptr(),
 			})
 			return diags