diff --git a/src/ModelingToolkit.jl b/src/ModelingToolkit.jl
index 8333840fb8..e0b406546f 100644
--- a/src/ModelingToolkit.jl
+++ b/src/ModelingToolkit.jl
@@ -166,6 +166,7 @@ export structural_simplify
 export DiscreteSystem, DiscreteProblem
 
 export calculate_jacobian, generate_jacobian, generate_function
+export calculate_control_jacobian, generate_control_jacobian
 export calculate_tgrad, generate_tgrad
 export calculate_gradient, generate_gradient
 export calculate_factorized_W, generate_factorized_W
diff --git a/src/systems/abstractsystem.jl b/src/systems/abstractsystem.jl
index 4f6edb0d54..3e9e15ac64 100644
--- a/src/systems/abstractsystem.jl
+++ b/src/systems/abstractsystem.jl
@@ -34,6 +34,18 @@ call will be cached in the system object.
 """
 function calculate_jacobian end
 
+"""
+```julia
+calculate_control_jacobian(sys::AbstractSystem)
+```
+
+Calculate the jacobian matrix of a system with respect to the system's controls.
+
+Returns a matrix of [`Num`](@ref) instances. The result from the first
+call will be cached in the system object.
+"""
+function calculate_control_jacobian end
+
 """
 ```julia
 calculate_factorized_W(sys::AbstractSystem)
@@ -140,10 +152,12 @@ for prop in [
              :iv
              :states
              :ps
+             :ctrls
              :defaults
              :observed
              :tgrad
              :jac
+             :ctrl_jac
              :Wfact
              :Wfact_t
              :systems
@@ -301,6 +315,7 @@ end
 
 namespace_variables(sys::AbstractSystem) = states(sys, states(sys))
 namespace_parameters(sys::AbstractSystem) = parameters(sys, parameters(sys))
+namespace_controls(sys::AbstractSystem) = controls(sys, controls(sys))
 
 function namespace_defaults(sys)
     defs = defaults(sys)
@@ -344,13 +359,21 @@ function states(sys::AbstractSystem)
     systems = get_systems(sys)
     unique(isempty(systems) ?
            sts :
-           [sts;reduce(vcat,namespace_variables.(systems))])
+           [sts; reduce(vcat,namespace_variables.(systems))])
 end
+
 function parameters(sys::AbstractSystem)
     ps = get_ps(sys)
     systems = get_systems(sys)
-    isempty(systems) ? ps : [ps;reduce(vcat,namespace_parameters.(systems))]
+    isempty(systems) ? ps : [ps; reduce(vcat,namespace_parameters.(systems))]
 end
+
+function controls(sys::AbstractSystem)
+    ctrls = get_ctrls(sys)
+    systems = get_systems(sys)
+    isempty(systems) ? ctrls : [ctrls; reduce(vcat,namespace_controls.(systems))]
+end
+
 function observed(sys::AbstractSystem)
     iv = independent_variable(sys)
     obs = get_observed(sys)
diff --git a/src/systems/control/controlsystem.jl b/src/systems/control/controlsystem.jl
index a398d17931..e19cdc921b 100644
--- a/src/systems/control/controlsystem.jl
+++ b/src/systems/control/controlsystem.jl
@@ -1,6 +1,6 @@
 abstract type AbstractControlSystem <: AbstractSystem end
 
-function namespace_controls(sys::AbstractSystem)
+function namespace_controls(sys::AbstractControlSystem)
     [rename(x,renamespace(nameof(sys),nameof(x))) for x in controls(sys)]
 end
 
diff --git a/src/systems/diffeqs/abstractodesystem.jl b/src/systems/diffeqs/abstractodesystem.jl
index bea6b3fa9c..c0a8cf2605 100644
--- a/src/systems/diffeqs/abstractodesystem.jl
+++ b/src/systems/diffeqs/abstractodesystem.jl
@@ -38,6 +38,28 @@ function calculate_jacobian(sys::AbstractODESystem;
     return jac
 end
 
+function calculate_control_jacobian(sys::AbstractODESystem;
+                                    sparse=false, simplify=false)
+    cache = get_ctrl_jac(sys)[]
+    if cache isa Tuple && cache[2] == (sparse, simplify)
+        return cache[1]
+    end
+
+    rhs = [eq.rhs for eq ∈ equations(sys)]
+
+    iv = get_iv(sys)
+    ctrls = controls(sys)
+
+    if sparse
+        jac = sparsejacobian(rhs, ctrls, simplify=simplify)
+    else
+        jac = jacobian(rhs, ctrls, simplify=simplify)
+    end
+
+    get_ctrl_jac(sys)[] = jac, (sparse, simplify) # cache Jacobian
+    return jac
+end
+
 function generate_tgrad(sys::AbstractODESystem, dvs = states(sys), ps = parameters(sys);
                         simplify=false, kwargs...)
     tgrad = calculate_tgrad(sys,simplify=simplify)
@@ -50,6 +72,12 @@ function generate_jacobian(sys::AbstractODESystem, dvs = states(sys), ps = param
     return build_function(jac, dvs, ps, get_iv(sys); kwargs...)
 end
 
+function generate_control_jacobian(sys::AbstractODESystem, dvs = states(sys), ps = parameters(sys);
+                                   simplify=false, sparse = false, kwargs...)
+    jac = calculate_control_jacobian(sys;simplify=simplify,sparse=sparse)
+    return build_function(jac, dvs, ps, get_iv(sys); kwargs...)
+end
+
 @noinline function throw_invalid_derivative(dervar, eq)
     msg = "The derivative variable must be isolated to the left-hand " *
     "side of the equation like `$dervar ~ ...`.\n Got $eq."
diff --git a/src/systems/diffeqs/odesystem.jl b/src/systems/diffeqs/odesystem.jl
index d811690f3a..555a286817 100644
--- a/src/systems/diffeqs/odesystem.jl
+++ b/src/systems/diffeqs/odesystem.jl
@@ -31,6 +31,9 @@ struct ODESystem <: AbstractODESystem
     states::Vector
     """Parameter variables. Must not contain the independent variable."""
     ps::Vector
+    """Control parameters (some subset of `ps`)."""
+    ctrls::Vector
+    """Observed states."""
     observed::Vector{Equation}
     """
     Time-derivative matrix. Note: this field will not be defined until
@@ -43,6 +46,11 @@ struct ODESystem <: AbstractODESystem
     """
     jac::RefValue{Any}
     """
+    Control Jacobian matrix. Note: this field will not be defined until
+    [`calculate_control_jacobian`](@ref) is called on the system.
+    """
+    ctrl_jac::RefValue{Any}
+    """
     `Wfact` matrix. Note: this field will not be defined until
     [`generate_factorized_W`](@ref) is called on the system.
     """
@@ -74,16 +82,17 @@ struct ODESystem <: AbstractODESystem
     """
     connection_type::Any
 
-    function ODESystem(deqs, iv, dvs, ps, observed, tgrad, jac, Wfact, Wfact_t, name, systems, defaults, structure, connection_type)
+    function ODESystem(deqs, iv, dvs, ps, ctrls, observed, tgrad, jac, ctrl_jac, Wfact, Wfact_t, name, systems, defaults, structure, connection_type)
         check_variables(dvs,iv)
         check_parameters(ps,iv)
         check_equations(deqs,iv)
-        new(deqs, iv, dvs, ps, observed, tgrad, jac, Wfact, Wfact_t, name, systems, defaults, structure, connection_type)
+        new(deqs, iv, dvs, ps, ctrls, observed, tgrad, jac, ctrl_jac, Wfact, Wfact_t, name, systems, defaults, structure, connection_type)
     end
 end
 
 function ODESystem(
                    deqs::AbstractVector{<:Equation}, iv, dvs, ps;
+                   controls  = Num[],
                    observed = Num[],
                    systems = ODESystem[],
                    name=gensym(:ODESystem),
@@ -92,9 +101,13 @@ function ODESystem(
                    defaults=_merge(Dict(default_u0), Dict(default_p)),
                    connection_type=nothing,
                   )
+    
+    @assert all(control -> any(isequal.(control, ps)), controls) "All controls must also be parameters."
+
     iv′ = value(scalarize(iv))
     dvs′ = value.(scalarize(dvs))
     ps′ = value.(scalarize(ps))
+    ctrl′ = value.(scalarize(controls))
 
     if !(isempty(default_u0) && isempty(default_p))
         Base.depwarn("`default_u0` and `default_p` are deprecated. Use `defaults` instead.", :ODESystem, force=true)
@@ -104,13 +117,14 @@ function ODESystem(
 
     tgrad = RefValue(Vector{Num}(undef, 0))
     jac = RefValue{Any}(Matrix{Num}(undef, 0, 0))
+    ctrl_jac = RefValue{Any}(Matrix{Num}(undef, 0, 0))
     Wfact   = RefValue(Matrix{Num}(undef, 0, 0))
     Wfact_t = RefValue(Matrix{Num}(undef, 0, 0))
     sysnames = nameof.(systems)
     if length(unique(sysnames)) != length(sysnames)
         throw(ArgumentError("System names must be unique."))
     end
-    ODESystem(deqs, iv′, dvs′, ps′, observed, tgrad, jac, Wfact, Wfact_t, name, systems, defaults, nothing, connection_type)
+    ODESystem(deqs, iv′, dvs′, ps′, ctrl′, observed, tgrad, jac, ctrl_jac, Wfact, Wfact_t, name, systems, defaults, nothing, connection_type)
 end
 
 vars(x::Sym) = Set([x])
@@ -349,4 +363,4 @@ function convert_system(::Type{<:ODESystem}, sys, t; name=nameof(sys))
     neweqs = map(sub, equations(sys))
     defs = Dict(sub(k) => sub(v) for (k, v) in defaults(sys))
     return ODESystem(neweqs, t, newsts, parameters(sys); defaults=defs, name=name)
-end
+end
\ No newline at end of file
diff --git a/src/systems/diffeqs/sdesystem.jl b/src/systems/diffeqs/sdesystem.jl
index b847a3f5b7..ee271a1e4f 100644
--- a/src/systems/diffeqs/sdesystem.jl
+++ b/src/systems/diffeqs/sdesystem.jl
@@ -37,7 +37,10 @@ struct SDESystem <: AbstractODESystem
     states::Vector
     """Parameter variables. Must not contain the independent variable."""
     ps::Vector
-    observed::Vector
+    """Control parameters (some subset of `ps`)."""
+    ctrls::Vector
+    """Observed states."""
+    observed::Vector{Equation}
     """
     Time-derivative matrix. Note: this field will not be defined until
     [`calculate_tgrad`](@ref) is called on the system.
@@ -49,6 +52,11 @@ struct SDESystem <: AbstractODESystem
     """
     jac::RefValue
     """
+    Control Jacobian matrix. Note: this field will not be defined until
+    [`calculate_control_jacobian`](@ref) is called on the system.
+    """
+    ctrl_jac::RefValue{Any}
+    """
     `Wfact` matrix. Note: this field will not be defined until
     [`generate_factorized_W`](@ref) is called on the system.
     """
@@ -76,16 +84,17 @@ struct SDESystem <: AbstractODESystem
     """
     connection_type::Any
 
-    function SDESystem(deqs, neqs, iv, dvs, ps, observed, tgrad, jac, Wfact, Wfact_t, name, systems, defaults, connection_type)
+    function SDESystem(deqs, neqs, iv, dvs, ps, ctrls, observed, tgrad, jac, ctrl_jac, Wfact, Wfact_t, name, systems, defaults, connection_type)
         check_variables(dvs,iv)
         check_parameters(ps,iv)
         check_equations(deqs,iv)
-        new(deqs, neqs, iv, dvs, ps, observed, tgrad, jac, Wfact, Wfact_t, name, systems, defaults, connection_type)
+        new(deqs, neqs, iv, dvs, ps, ctrls, observed, tgrad, jac, ctrl_jac, Wfact, Wfact_t, name, systems, defaults, connection_type)
     end
 end
 
 function SDESystem(deqs::AbstractVector{<:Equation}, neqs, iv, dvs, ps;
-                   observed = [],
+                   controls = Num[],
+                   observed = Num[],
                    systems = SDESystem[],
                    default_u0=Dict(),
                    default_p=Dict(),
@@ -96,6 +105,8 @@ function SDESystem(deqs::AbstractVector{<:Equation}, neqs, iv, dvs, ps;
     iv′ = value(iv)
     dvs′ = value.(dvs)
     ps′ = value.(ps)
+    ctrl′ = value.(controls)
+
     sysnames = nameof.(systems)
     if length(unique(sysnames)) != length(sysnames)
         throw(ArgumentError("System names must be unique."))
@@ -108,9 +119,10 @@ function SDESystem(deqs::AbstractVector{<:Equation}, neqs, iv, dvs, ps;
 
     tgrad = RefValue(Vector{Num}(undef, 0))
     jac = RefValue{Any}(Matrix{Num}(undef, 0, 0))
+    ctrl_jac = RefValue{Any}(Matrix{Num}(undef, 0, 0))
     Wfact   = RefValue(Matrix{Num}(undef, 0, 0))
     Wfact_t = RefValue(Matrix{Num}(undef, 0, 0))
-    SDESystem(deqs, neqs, iv′, dvs′, ps′, observed, tgrad, jac, Wfact, Wfact_t, name, systems, defaults, connection_type)
+    SDESystem(deqs, neqs, iv′, dvs′, ps′, ctrl′, observed, tgrad, jac, ctrl_jac, Wfact, Wfact_t, name, systems, defaults, connection_type)
 end
 
 function generate_diffusion_function(sys::SDESystem, dvs = states(sys), ps = parameters(sys); kwargs...)
@@ -157,10 +169,6 @@ function stochastic_integral_transform(sys::SDESystem, correction_factor)
     SDESystem(deqs,get_noiseeqs(sys),get_iv(sys),states(sys),parameters(sys))
 end
 
-
-
-
-
 """
 ```julia
 function DiffEqBase.SDEFunction{iip}(sys::SDESystem, dvs = sys.states, ps = sys.ps;
diff --git a/src/systems/discrete_system/discrete_system.jl b/src/systems/discrete_system/discrete_system.jl
index 58b2bc1baa..afc2dd699c 100644
--- a/src/systems/discrete_system/discrete_system.jl
+++ b/src/systems/discrete_system/discrete_system.jl
@@ -30,6 +30,9 @@ struct DiscreteSystem <: AbstractSystem
     states::Vector
     """Parameter variables. Must not contain the independent variable."""
     ps::Vector
+    """Control parameters (some subset of `ps`)."""
+    ctrls::Vector
+    """Observed states."""
     observed::Vector{Equation}
     """
     Name: the name of the system
@@ -49,10 +52,10 @@ struct DiscreteSystem <: AbstractSystem
     in `DiscreteSystem`.
     """
     default_p::Dict
-    function DiscreteSystem(discreteEqs, iv, dvs, ps, observed, name, systems, default_u0, default_p)
-        check_variables(dvs, iv)
-        check_parameters(ps, iv)
-        new(discreteEqs, iv, dvs, ps, observed, name, systems, default_u0, default_p)
+    function DiscreteSystem(discreteEqs, iv, dvs, ps, ctrls, observed, name, systems, default_u0, default_p)
+        check_variables(dvs,iv)
+        check_parameters(ps,iv)
+        new(discreteEqs, iv, dvs, ps, ctrls, observed, name, systems, default_u0, default_p)
     end
 end
 
@@ -63,6 +66,7 @@ Constructs a DiscreteSystem.
 """
 function DiscreteSystem(
                    discreteEqs::AbstractVector{<:Equation}, iv, dvs, ps;
+                   controls = Num[],
                    observed = Num[],
                    systems = DiscreteSystem[],
                    name=gensym(:DiscreteSystem),
@@ -72,6 +76,7 @@ function DiscreteSystem(
     iv′ = value(iv)
     dvs′ = value.(dvs)
     ps′ = value.(ps)
+    ctrl′ = value.(controls)
 
     default_u0 isa Dict || (default_u0 = Dict(default_u0))
     default_p isa Dict || (default_p = Dict(default_p))
@@ -82,7 +87,7 @@ function DiscreteSystem(
     if length(unique(sysnames)) != length(sysnames)
         throw(ArgumentError("System names must be unique."))
     end
-    DiscreteSystem(discreteEqs, iv′, dvs′, ps′, observed, name, systems, default_u0, default_p)
+    DiscreteSystem(discreteEqs, iv′, dvs′, ps′, ctrl′, observed, name, systems, default_u0, default_p)
 end
 
 """
diff --git a/test/direct.jl b/test/direct.jl
index 77562946e4..2c69749c82 100644
--- a/test/direct.jl
+++ b/test/direct.jl
@@ -75,7 +75,7 @@ end
 @variables a,b
 X = [a,b]
 
-spoly(x) = simplify(x, polynorm=true)
+spoly(x) = simplify(x, expand=true)
 rr = rosenbrock(X)
 
 reference_hes = ModelingToolkit.hessian(rr, X)
diff --git a/test/discretesystem.jl b/test/discretesystem.jl
index 24f44dc092..224159d07e 100644
--- a/test/discretesystem.jl
+++ b/test/discretesystem.jl
@@ -22,7 +22,7 @@ eqs = [next_S ~ S-infection,
        next_R ~ R+recovery]
 
 # System
-sys = DiscreteSystem(eqs,t,[S,I,R],[c,nsteps,δt,β,γ])
+sys = DiscreteSystem(eqs,t,[S,I,R],[c,nsteps,δt,β,γ]; controls = [β, γ])
 
 # Problem
 u0 = [S => 990.0, I => 10.0, R => 0.0]
@@ -54,4 +54,4 @@ p = [0.05,10.0,0.25,0.1];
 prob_map = DiscreteProblem(sir_map!,u0,tspan,p);
 sol_map2 = solve(prob_map,FunctionMap());
 
-@test Array(sol_map) ≈ Array(sol_map2)
+@test Array(sol_map) ≈ Array(sol_map2)
\ No newline at end of file
diff --git a/test/odesystem.jl b/test/odesystem.jl
index 91074e4621..67cdbad665 100644
--- a/test/odesystem.jl
+++ b/test/odesystem.jl
@@ -361,4 +361,22 @@ D =Differential(t)
 eqs = [D(x1) ~ -x1]
 sys = ODESystem(eqs,t,[x1,x2],[])
 @test_throws ArgumentError ODEProblem(sys, [1.0,1.0], (0.0,1.0))
-prob = ODEProblem(sys, [1.0,1.0], (0.0,1.0), check_length=false)
\ No newline at end of file
+prob = ODEProblem(sys, [1.0,1.0], (0.0,1.0), check_length=false)
+
+# check inputs
+let 
+    @parameters t f k d
+    @variables x(t) ẋ(t)
+    δ = Differential(t)
+    
+    eqs = [δ(x) ~ ẋ, δ(ẋ) ~ f - k*x - d*ẋ]
+    sys = ODESystem(eqs, t, [x, ẋ], [f, d, k]; controls = [f])
+
+    calculate_control_jacobian(sys)
+
+    @test isequal(
+        calculate_control_jacobian(sys),
+        reshape(Num[0,1], 2, 1)
+    )
+
+end
\ No newline at end of file
diff --git a/test/reduction.jl b/test/reduction.jl
index 18abcd768d..89c968454d 100644
--- a/test/reduction.jl
+++ b/test/reduction.jl
@@ -27,7 +27,7 @@ ref_eq = [
 @variables x(t) y(t) z(t) a(t) u(t) F(t)
 D = Differential(t)
 
-test_equal(a, b) = @test isequal(simplify(a, polynorm=true), simplify(b, polynorm=true))
+test_equal(a, b) = @test isequal(simplify(a, expand=true), simplify(b, expand=true))
 
 eqs = [
        D(x) ~ σ*(y-x)