diff --git a/src/core/settings.jl b/src/core/settings.jl
index 063ad1cce0..beda9f133a 100644
--- a/src/core/settings.jl
+++ b/src/core/settings.jl
@@ -57,7 +57,7 @@ function Settings(
         optimizer_ = MOI.OptimizerWithAttributes(optimizer)
     else
         error(
-            "The provided input for optimizer is invalid. Provide a JuMP.OptimizerWithAttributes object or a valid Optimizer constructor (e.g. GLPK.Optimizer).",
+            "The provided input for optimizer is invalid. Provide a JuMP.OptimizerWithAttributes object or a valid Optimizer constructor (e.g. HiGHS.Optimizer).",
         )
     end
 
diff --git a/src/operation/emulation_model.jl b/src/operation/emulation_model.jl
index cd42d60ec9..f75a7c9f36 100644
--- a/src/operation/emulation_model.jl
+++ b/src/operation/emulation_model.jl
@@ -536,8 +536,8 @@ keyword arguments to that function.
 # Examples
 
 ```julia
-status = run!(model; optimizer = GLPK.Optimizer, executions = 10)
-status = run!(model; output_dir = ./model_output, optimizer = GLPK.Optimizer, executions = 10)
+status = run!(model; optimizer = HiGHS.Optimizer, executions = 10)
+status = run!(model; output_dir = ./model_output, optimizer = HiGHS.Optimizer, executions = 10)
 ```
 """
 function run!(
diff --git a/test/Project.toml b/test/Project.toml
index e15b719fbc..2f4a74bacb 100644
--- a/test/Project.toml
+++ b/test/Project.toml
@@ -1,11 +1,9 @@
 [deps]
 Aqua = "4c88cf16-eb10-579e-8560-4a9242c79595"
 CSV = "336ed68f-0bac-5ca0-87d4-7b16caf5d00b"
-Cbc = "9961bab8-2fa3-5c5a-9d89-47fab24efd76"
 DataFrames = "a93c6f00-e57d-5684-b7b6-d8193f3e46c0"
 DataStructures = "864edb3b-99cc-5e75-8d2d-829cb0a9cfe8"
 Dates = "ade2ca70-3891-5945-98fb-dc099432e06a"
-GLPK = "60bf3e95-4087-53dc-ae20-288a0d20c6a6"
 HiGHS = "87dc4568-4c63-4d18-b0c0-bb2238e4078b"
 HydroPowerSimulations = "fc1677e0-6ad7-4515-bf3a-bd6bf20a0b1b"
 InfrastructureSystems = "2cd47ed4-ca9b-11e9-27f2-ab636a7671f1"
@@ -13,7 +11,6 @@ Ipopt = "b6b21f68-93f8-5de0-b562-5493be1d77c9"
 JSON3 = "0f8b85d8-7281-11e9-16c2-39a750bddbf1"
 JuMP = "4076af6c-e467-56ae-b986-b466b2749572"
 Logging = "56ddb016-857b-54e1-b83d-db4d58db5568"
-Memento = "f28f55f0-a522-5efc-85c2-fe41dfb9b2d9"
 Pkg = "44cfe95a-1eb2-52ea-b672-e2afdf69b78f"
 PowerModels = "c36e90e8-916a-50a6-bd94-075b64ef4655"
 PowerNetworkMatrices = "bed98974-b02a-5e2f-9fe0-a103f5c450dd"
diff --git a/test/test_device_thermal_generation_constructors.jl b/test/test_device_thermal_generation_constructors.jl
index cdb3a38813..8525b3e5e7 100644
--- a/test/test_device_thermal_generation_constructors.jl
+++ b/test/test_device_thermal_generation_constructors.jl
@@ -723,7 +723,7 @@ end
         UnitCommitmentProblem,
         template,
         sys;
-        optimizer = cbc_optimizer,
+        optimizer = HiGHS_optimizer,
         initialize_model = false,
     )
     @test build!(UC; output_dir = mktempdir(; cleanup = true)) == PSI.ModelBuildStatus.BUILT
diff --git a/test/test_model_decision.jl b/test/test_model_decision.jl
index fbcdc0392c..6b1d1abc97 100644
--- a/test/test_model_decision.jl
+++ b/test/test_model_decision.jl
@@ -5,7 +5,7 @@
 
     @test_throws MethodError DecisionModel(template, c_sys5; bad_kwarg = 10)
 
-    model = DecisionModel(template, c_sys5; optimizer = GLPK_optimizer)
+    model = DecisionModel(template, c_sys5; optimizer = HiGHS_optimizer)
     @test build!(model; output_dir = mktempdir(; cleanup = true)) ==
           PSI.ModelBuildStatus.BUILT
 
@@ -15,14 +15,14 @@
             NetworkModel(CopperPlatePowerModel; use_slacks = true),
         ),
         c_sys5_re;
-        optimizer = GLPK_optimizer,
+        optimizer = HiGHS_optimizer,
     )
     @test build!(model; output_dir = mktempdir(; cleanup = true)) ==
           PSI.ModelBuildStatus.BUILT
     model = DecisionModel(
         get_thermal_dispatch_template_network(),
         c_sys5;
-        optimizer = GLPK_optimizer,
+        optimizer = HiGHS_optimizer,
     )
     @test build!(model; output_dir = mktempdir(; cleanup = true)) ==
           PSI.ModelBuildStatus.BUILT
@@ -35,7 +35,7 @@
         get_thermal_dispatch_template_network(),
         c_sys5,
         my_model;
-        optimizer = GLPK_optimizer,
+        optimizer = HiGHS_optimizer,
     )
     @test build!(model; output_dir = mktempdir(; cleanup = true)) ==
           PSI.ModelBuildStatus.BUILT
@@ -49,10 +49,10 @@ end
         template,
         ServiceModel(VariableReserve{ReserveUp}, RangeReserve, "test"),
     )
-    UC = DecisionModel(template, c_sys5; optimizer = GLPK_optimizer)
+    UC = DecisionModel(template, c_sys5; optimizer = HiGHS_optimizer)
     output_dir = mktempdir(; cleanup = true)
     @test build!(UC; output_dir = output_dir) == PSI.ModelBuildStatus.BUILT
-    @test solve!(UC; optimizer = GLPK_optimizer) == PSI.RunStatus.SUCCESSFULLY_FINALIZED
+    @test solve!(UC; optimizer = HiGHS_optimizer) == PSI.RunStatus.SUCCESSFULLY_FINALIZED
     res = OptimizationProblemResults(UC)
     @test isapprox(get_objective_value(res), 340000.0; atol = 100000.0)
     vars = res.variable_values
@@ -98,7 +98,7 @@ end
         template,
         ServiceModel(VariableReserve{ReserveUp}, RangeReserve, "test"),
     )
-    model = DecisionModel(template, c_sys5; optimizer = GLPK_optimizer)
+    model = DecisionModel(template, c_sys5; optimizer = HiGHS_optimizer)
     @test build!(model; output_dir = mktempdir(; cleanup = true)) ==
           PSI.ModelBuildStatus.BUILT
     container = PSI.get_optimization_container(model)
@@ -245,10 +245,10 @@ end
         template,
         ServiceModel(VariableReserve{ReserveUp}, RangeReserve, "test"),
     )
-    UC = DecisionModel(template, c_sys5; optimizer = GLPK_optimizer)
+    UC = DecisionModel(template, c_sys5; optimizer = HiGHS_optimizer)
     output_dir = mktempdir(; cleanup = true)
     @test_throws ErrorException solve!(UC)
-    @test solve!(UC; optimizer = GLPK_optimizer, output_dir = output_dir) ==
+    @test solve!(UC; optimizer = HiGHS_optimizer, output_dir = output_dir) ==
           PSI.RunStatus.SUCCESSFULLY_FINALIZED
 end
 
@@ -357,7 +357,7 @@ end
     c_sys5 = PSB.build_system(PSITestSystems, "c_sys5")
     valid_bounds =
         (coefficient = (min = 1.0, max = 1.0), rhs = (min = 0.4, max = 9.930296584))
-    model = DecisionModel(template, c_sys5; optimizer = GLPK_optimizer)
+    model = DecisionModel(template, c_sys5; optimizer = HiGHS_optimizer)
     @test build!(model; output_dir = mktempdir(; cleanup = true)) ==
           PSI.ModelBuildStatus.BUILT
 
@@ -387,7 +387,7 @@ end
     template = get_template_basic_uc_simulation()
     c_sys5 = PSB.build_system(PSITestSystems, "c_sys5_uc")
     valid_bounds = (min = 0.0, max = 6.0)
-    model = DecisionModel(template, c_sys5; optimizer = GLPK_optimizer)
+    model = DecisionModel(template, c_sys5; optimizer = HiGHS_optimizer)
     @test build!(model; output_dir = mktempdir(; cleanup = true)) ==
           PSI.ModelBuildStatus.BUILT
 
@@ -494,7 +494,7 @@ end
         template,
         ServiceModel(VariableReserve{ReserveUp}, RangeReserve, "test"),
     )
-    optimizer = GLPK_optimizer
+    optimizer = HiGHS_optimizer
 
     # Construct and build with default behavior that builds initial conditions.
     model = DecisionModel(template, sys; optimizer = optimizer)
@@ -575,7 +575,7 @@ end
     UC = DecisionModel(
         template,
         c_sys5;
-        optimizer = GLPK_optimizer,
+        optimizer = HiGHS_optimizer,
         detailed_optimizer_stats = true,
     )
     output_dir = mktempdir(; cleanup = true)
@@ -601,7 +601,7 @@ end
     UC = DecisionModel(
         template,
         c_sys5;
-        optimizer = GLPK_optimizer,
+        optimizer = HiGHS_optimizer,
         detailed_optimizer_stats = true,
     )
     output_dir = mktempdir(; cleanup = true)
@@ -645,7 +645,7 @@ end
     UC = DecisionModel(
         template,
         c_sys5;
-        optimizer = GLPK_optimizer,
+        optimizer = HiGHS_optimizer,
         detailed_optimizer_stats = true,
     )
     output_dir = mktempdir(; cleanup = true)
@@ -672,7 +672,7 @@ end
     model = DecisionModel(
         template,
         c_sys5_bat;
-        optimizer = GLPK_optimizer,
+        optimizer = HiGHS_optimizer,
     )
     @test build!(model; output_dir = output_dir) == PSI.ModelBuildStatus.BUILT
     @test solve!(model) == PSI.RunStatus.SUCCESSFULLY_FINALIZED
diff --git a/test/test_model_emulation.jl b/test/test_model_emulation.jl
index 9688073310..5abd81db88 100644
--- a/test/test_model_emulation.jl
+++ b/test/test_model_emulation.jl
@@ -7,7 +7,7 @@
         force_build = true,
     )
 
-    model = EmulationModel(template, c_sys5; optimizer = GLPK_optimizer)
+    model = EmulationModel(template, c_sys5; optimizer = HiGHS_optimizer)
     @test build!(model; executions = 10, output_dir = mktempdir(; cleanup = true)) ==
           PSI.ModelBuildStatus.BUILT
     @test run!(model) == PSI.RunStatus.SUCCESSFULLY_FINALIZED
@@ -20,7 +20,7 @@
         force_build = true,
     )
     set_device_model!(template, RenewableDispatch, RenewableFullDispatch)
-    model = EmulationModel(template, c_sys5_uc_re; optimizer = GLPK_optimizer)
+    model = EmulationModel(template, c_sys5_uc_re; optimizer = HiGHS_optimizer)
 
     @test build!(model; executions = 10, output_dir = mktempdir(; cleanup = true)) ==
           PSI.ModelBuildStatus.BUILT
@@ -315,7 +315,7 @@ end
     # Deserialize with a different optimizer.
     @test_logs (:warn, r"Original solver was .* new solver is") match_mode = :any EmulationModel(
         path,
-        GLPK_optimizer,
+        HiGHS_optimizer,
     )
 end
 
diff --git a/test/test_network_constructors.jl b/test/test_network_constructors.jl
index 2b90bb6480..70393c13c0 100644
--- a/test/test_network_constructors.jl
+++ b/test/test_network_constructors.jl
@@ -1,4 +1,4 @@
-# Note to devs. Use GLPK or Cbc for models with linear constraints and linear cost functions
+# Note to devs. Use HiGHS for models with linear constraints and linear cost functions
 # Use OSQP for models with quadratic cost function and linear constraints and ipopt otherwise
 
 @testset "All PowerModels models construction" begin
@@ -59,7 +59,7 @@ end
     ps_model_re = DecisionModel(
         template,
         PSB.build_system(PSITestSystems, "c_sys5_re");
-        optimizer = GLPK_optimizer,
+        optimizer = HiGHS_optimizer,
     )
     @test build!(ps_model_re; output_dir = mktempdir(; cleanup = true)) ==
           PSI.ModelBuildStatus.BUILT
@@ -121,7 +121,7 @@ end
         )
     end
     # PTDF input Error testing
-    ps_model = DecisionModel(template, c_sys5; optimizer = GLPK_optimizer)
+    ps_model = DecisionModel(template, c_sys5; optimizer = HiGHS_optimizer)
     @test build!(
         ps_model;
         console_level = Logging.AboveMaxLevel,  # Ignore expected errors.
@@ -644,7 +644,7 @@ end
         set_device_model!(template_uc, ThermalStandard, thermal_model)
 
         ##### Solve Reduced Model ####
-        solver = GLPK_optimizer
+        solver = HiGHS_optimizer
         uc_model_red = DecisionModel(
             template_uc,
             new_sys;
diff --git a/test/test_print.jl b/test/test_print.jl
index 2a19c5956c..4bc08eb92d 100644
--- a/test/test_print.jl
+++ b/test/test_print.jl
@@ -22,10 +22,10 @@ end
     template = get_thermal_dispatch_template_network()
     c_sys5 = PSB.build_system(PSITestSystems, "c_sys5")
 
-    dm_model = DecisionModel(template, c_sys5; optimizer = GLPK_optimizer)
+    dm_model = DecisionModel(template, c_sys5; optimizer = HiGHS_optimizer)
     @test build!(dm_model; output_dir = mktempdir(; cleanup = true)) ==
           PSI.ModelBuildStatus.BUILT
-    @test solve!(dm_model; optimizer = GLPK_optimizer) ==
+    @test solve!(dm_model; optimizer = HiGHS_optimizer) ==
           PSI.RunStatus.SUCCESSFULLY_FINALIZED
     results = OptimizationProblemResults(dm_model)
     variables = read_variables(results)
diff --git a/test/test_recorder_events.jl b/test/test_recorder_events.jl
index 3de10be804..a217142658 100644
--- a/test/test_recorder_events.jl
+++ b/test/test_recorder_events.jl
@@ -7,7 +7,7 @@
         force_build = true,
     )
     set_device_model!(template, RenewableDispatch, RenewableFullDispatch)
-    model = EmulationModel(template, c_sys5_uc_re; optimizer = GLPK_optimizer)
+    model = EmulationModel(template, c_sys5_uc_re; optimizer = HiGHS_optimizer)
 
     @test build!(model; executions = 10, output_dir = mktempdir(; cleanup = true)) ==
           PSI.ModelBuildStatus.BUILT
diff --git a/test/test_services_constructor.jl b/test/test_services_constructor.jl
index ce3d8b712c..203451baac 100644
--- a/test/test_services_constructor.jl
+++ b/test/test_services_constructor.jl
@@ -96,7 +96,7 @@ end
     )
     c_sys5_uc = PSB.build_system(PSITestSystems, "c_sys5_uc"; add_reserves = true)
 
-    model = DecisionModel(template, c_sys5_uc; optimizer = cbc_optimizer)
+    model = DecisionModel(template, c_sys5_uc; optimizer = HiGHS_optimizer)
     @test build!(model; output_dir = mktempdir(; cleanup = true)) ==
           PSI.ModelBuildStatus.BUILT
     moi_tests(model, 984, 0, 576, 216, 168, true)
diff --git a/test/test_simulation_execute.jl b/test/test_simulation_execute.jl
index d22a2efaba..4ca9b4f36d 100644
--- a/test/test_simulation_execute.jl
+++ b/test/test_simulation_execute.jl
@@ -329,7 +329,7 @@ end
                 UnitCommitmentProblem,
                 template,
                 PSB.build_system(PSITestSystems, "c_market_bid_cost");
-                optimizer = cbc_optimizer,
+                optimizer = HiGHS_optimizer,
                 initialize_model = false,
             ),
         ],
diff --git a/test/test_utils/mock_operation_models.jl b/test/test_utils/mock_operation_models.jl
index b66d5be01c..c776c28224 100644
--- a/test/test_utils/mock_operation_models.jl
+++ b/test/test_utils/mock_operation_models.jl
@@ -196,8 +196,8 @@ function create_simulation_build_test_problems(
 )
     return SimulationModels(;
         decision_models = [
-            DecisionModel(template_uc, sys_uc; name = "UC", optimizer = GLPK_optimizer),
-            DecisionModel(template_ed, sys_ed; name = "ED", optimizer = GLPK_optimizer),
+            DecisionModel(template_uc, sys_uc; name = "UC", optimizer = HiGHS_optimizer),
+            DecisionModel(template_ed, sys_ed; name = "ED", optimizer = HiGHS_optimizer),
         ],
     )
 end
diff --git a/test/test_utils/solver_definitions.jl b/test/test_utils/solver_definitions.jl
index a7ef5acdb7..795b195bb7 100644
--- a/test/test_utils/solver_definitions.jl
+++ b/test/test_utils/solver_definitions.jl
@@ -13,8 +13,6 @@ fast_ipopt_optimizer = JuMP.optimizer_with_attributes(
     "max_cpu_time" => 5.0,
 )
 # use default print_level = 5 # set to 0 to disable
-GLPK_optimizer =
-    JuMP.optimizer_with_attributes(GLPK.Optimizer, "msg_lev" => GLPK.GLP_MSG_OFF)
 scs_solver = JuMP.optimizer_with_attributes(
     SCS.Optimizer,
     "max_iters" => 100000,
@@ -27,5 +25,3 @@ HiGHS_optimizer = JuMP.optimizer_with_attributes(
     "time_limit" => 100.0,
     "log_to_console" => false,
 )
-
-cbc_optimizer = JuMP.optimizer_with_attributes(Cbc.Optimizer)