diff --git a/README.md b/README.md
index ee975b3..51aa002 100644
--- a/README.md
+++ b/README.md
@@ -3,7 +3,7 @@
 
 A simple state machine definition language and interpreter.
 
-A state machine is composed of states - stages of the machine which are run until an exit condition is met and the machine moves to the next stage. State machines in `shakemyleg` are defined as a series of expressions which are run every time the machine runs - the "head". Along with the head is the body - a list of conditions which, when evaluate `true`, run a series of expressions and a `StateOp` (`changeto <state>`, `stay`, `end`). If no condition is true, no action is taken. Conditions are visited in order.
+A state machine is composed of states - stages of the machine which are run until an exit condition is met and the machine moves to the next stage. State machines in `shakemyleg` are defined as a series of expressions which are run every time the machine runs - the "head". Along with the head is the body - a list of conditions which, when evaluate `true`, run a series of expressions and a `StateOp` (`changeto <state>`, `stay`, `end`). If no condition is true, no action is taken. Conditions are visited in order. Comments start with a `#`.
 
 A very simple example `shakemyleg` machine:
 ```sml
diff --git a/src/compiler.rs b/src/compiler.rs
index 32c2f76..e10d3f9 100644
--- a/src/compiler.rs
+++ b/src/compiler.rs
@@ -154,10 +154,16 @@ pub fn compile(s: &str) -> SML_Result<StateMachine> {
     let mut states = Vec::new();
     let mut leading_ws = None;
 
-    loop {
+    let nlines = lines.len();
+    while i < nlines {
         let line = lines[i];
         let cstate = c_state_stack.last().unwrap();
 
+        if line.trim_start().starts_with("#") {
+            i += 1;
+            continue;
+        }
+
         if leading_ws.is_none() && matches!(cstate, CompileState::Globals | CompileState::State) {
             let line_no_ws = line.trim_start();
             let ws = line.strip_suffix(line_no_ws).unwrap();
@@ -273,9 +279,6 @@ pub fn compile(s: &str) -> SML_Result<StateMachine> {
 
         if adv {
             i += 1;
-            if i >= lines.len() {
-                break;
-            }
         }
     }