diff --git a/src/state_indexing.jl b/src/state_indexing.jl
index d84e869..f2cd7f2 100644
--- a/src/state_indexing.jl
+++ b/src/state_indexing.jl
@@ -189,27 +189,67 @@ for (t1, t2) in [
     (NotSymbolic, Union{<:Tuple, <:AbstractArray}),
 ]
     @eval function _getu(sys, ::NotSymbolic, ::$t1, sym::$t2)
-        getters = getu.((sys,), sym)
-        _call(getter, args...) = getter(args...)
-        return let getters = getters, _call = _call
-            _getter(::NotTimeseries, prob) = map(g -> g(prob), getters)
-            function _getter(::Timeseries, prob)
-                broadcast(i -> map(g -> _call(g, prob, i), getters),
-                    eachindex(state_values(prob)))
-            end
-            function _getter(::Timeseries, prob, i)
-                return map(g -> _call(g, prob, i), getters)
-            end
+        num_observed = count(x -> is_observed(sys, x), sym)
+        if num_observed <= 1
+            getters = getu.((sys,), sym)
+            _call(getter, args...) = getter(args...)
+            return let getters = getters, _call = _call
+                _getter(::NotTimeseries, prob) = map(g -> g(prob), getters)
+                function _getter(::Timeseries, prob)
+                    broadcast(i -> map(g -> _call(g, prob, i), getters),
+                        eachindex(state_values(prob)))
+                end
+                function _getter(::Timeseries, prob, i)
+                    return map(g -> _call(g, prob, i), getters)
+                end
 
-            # Need another scope for this to not box `_getter`
-            let _getter = _getter
-                function getter(prob)
-                    return _getter(is_timeseries(prob), prob)
+                # Need another scope for this to not box `_getter`
+                let _getter = _getter
+                    function getter(prob)
+                        return _getter(is_timeseries(prob), prob)
+                    end
+                    function getter(prob, i)
+                        return _getter(is_timeseries(prob), prob, i)
+                    end
+                    getter
+                end
+            end
+        else
+            obs = observed(sys, sym isa Tuple ? collect(sym) : sym)
+            return let obs = obs, is_tuple = sym isa Tuple
+                function _getter2(::NotTimeseries, prob)
+                    obs(state_values(prob), parameter_values(prob), current_time(prob))
+                end
+                function _getter2(::Timeseries, prob)
+                    obs.(state_values(prob), (parameter_values(prob),), current_time(prob))
                 end
-                function getter(prob, i)
-                    return _getter(is_timeseries(prob), prob, i)
+                function _getter2(::Timeseries, prob, i)
+                    obs(state_values(prob, i),
+                        parameter_values(prob),
+                        current_time(prob, i))
+                end
+
+                if is_tuple
+                    let _getter2 = _getter2
+                        function getter2(prob)
+                            Tuple(_getter2(is_timeseries(prob), prob))
+                        end
+                        function getter2(prob, i)
+                            Tuple(_getter2(is_timeseries(prob), prob, i))
+                        end
+                        getter2
+                    end
+                else
+                    let _getter2 = _getter2
+                        function getter3(prob)
+                            _getter2(is_timeseries(prob), prob)
+                        end
+                        function getter3(prob, i)
+                            _getter2(is_timeseries(prob), prob, i)
+                        end
+                        getter3
+                    end
                 end
-                getter
             end
         end
     end