diff --git a/command/jsonplan/plan.go b/command/jsonplan/plan.go
index 5a828ccce..4d8dccd95 100644
--- a/command/jsonplan/plan.go
+++ b/command/jsonplan/plan.go
@@ -522,6 +522,11 @@ func sensitiveAsBool(val cty.Value) cty.Value {
 	case val.IsNull(), ty.IsPrimitiveType(), ty.Equals(cty.DynamicPseudoType):
 		return cty.False
 	case ty.IsListType() || ty.IsTupleType() || ty.IsSetType():
+		if !val.IsKnown() {
+			// If the collection is unknown we can't say anything about the
+			// sensitivity of its contents
+			return cty.EmptyTupleVal
+		}
 		length := val.LengthInt()
 		if length == 0 {
 			// If there are no elements then we can't have sensitive values
@@ -540,6 +545,11 @@ func sensitiveAsBool(val cty.Value) cty.Value {
 		// indistinguishable in JSON.
 		return cty.TupleVal(vals)
 	case ty.IsMapType() || ty.IsObjectType():
+		if !val.IsKnown() {
+			// If the map/object is unknown we can't say anything about the
+			// sensitivity of its attributes
+			return cty.EmptyObjectVal
+		}
 		var length int
 		switch {
 		case ty.IsMapType():
diff --git a/command/jsonplan/plan_test.go b/command/jsonplan/plan_test.go
index f6ee837fe..9d43d1dc5 100644
--- a/command/jsonplan/plan_test.go
+++ b/command/jsonplan/plan_test.go
@@ -447,6 +447,22 @@ func TestSensitiveAsBool(t *testing.T) {
 				cty.EmptyObjectVal,
 			}),
 		},
+		{
+			cty.ObjectVal(map[string]cty.Value{
+				"list":   cty.UnknownVal(cty.List(cty.String)),
+				"set":    cty.UnknownVal(cty.Set(cty.Bool)),
+				"tuple":  cty.UnknownVal(cty.Tuple([]cty.Type{cty.String, cty.Number})),
+				"map":    cty.UnknownVal(cty.Map(cty.String)),
+				"object": cty.UnknownVal(cty.Object(map[string]cty.Type{"a": cty.String})),
+			}),
+			cty.ObjectVal(map[string]cty.Value{
+				"list":   cty.EmptyTupleVal,
+				"set":    cty.EmptyTupleVal,
+				"tuple":  cty.EmptyTupleVal,
+				"map":    cty.EmptyObjectVal,
+				"object": cty.EmptyObjectVal,
+			}),
+		},
 	}
 
 	for _, test := range tests {