diff --git a/internal/funcs/1.3/functions.go b/internal/funcs/1.3/functions.go
index 62219998..1e6b9caa 100644
--- a/internal/funcs/1.3/functions.go
+++ b/internal/funcs/1.3/functions.go
@@ -3,6 +3,8 @@ package funcs
 import (
 	"github.com/hashicorp/go-version"
 	"github.com/hashicorp/hcl-lang/schema"
+	"github.com/zclconf/go-cty/cty"
+	"github.com/zclconf/go-cty/cty/function"
 
 	funcs_v0_15 "github.com/hashicorp/terraform-schema/internal/funcs/0.15"
 )
@@ -12,7 +14,22 @@ func Functions(v *version.Version) map[string]schema.FuncSignature {
 
 	f["endswith"] = schema.FuncSignature{}   // TODO!
 	f["startswith"] = schema.FuncSignature{} // TODO!
-	f["timecmp"] = schema.FuncSignature{}    // TODO!
+	f["timecmp"] = schema.FuncSignature{
+		Description: "timecmp compares two timestamps and returns a number that represents the ordering of the instants those timestamps represent.",
+		Params: []function.Parameter{
+			{
+				Name:        "timestamp_a",
+				Description: "First timestamp for comparison.",
+				Type:        cty.String,
+			},
+			{
+				Name:        "timestamp_b",
+				Description: "Second timestamp for comparison.",
+				Type:        cty.String,
+			},
+		},
+		ReturnTypes: cty.Number,
+	}
 
 	return f
 }