diff --git a/.changes/20260827_131104_cardano-cli_palas_dijkstra_pparam_updates.yml b/.changes/20260827_131104_cardano-cli_palas_dijkstra_pparam_updates.yml
new file mode 100644
index 0000000000..ef1c351479
--- /dev/null
+++ b/.changes/20260827_131104_cardano-cli_palas_dijkstra_pparam_updates.yml
@@ -0,0 +1,6 @@
+description: |
+  Protocol-parameter update proposals can now be created in the Dijkstra era with `governance action create-protocol-parameters-update`, including cost models and the parameters the era introduces: maximum reference-script size per block and per transaction, and the reference-script cost stride and multiplier.
+kind:
+- feature
+pr: 1429
+project: cardano-cli
diff --git a/cardano-cli/src/Cardano/CLI/EraBased/Governance/Actions/Option.hs b/cardano-cli/src/Cardano/CLI/EraBased/Governance/Actions/Option.hs
index 72a7918043..bc9a51f7b7 100644
--- a/cardano-cli/src/Cardano/CLI/EraBased/Governance/Actions/Option.hs
+++ b/cardano-cli/src/Cardano/CLI/EraBased/Governance/Actions/Option.hs
@@ -21,6 +21,7 @@ import Cardano.CLI.EraBased.Governance.Actions.Command qualified as Cmd
 import Cardano.CLI.Option.Flag (setDefault)
 import Cardano.CLI.Parser
 import Cardano.CLI.Type.Common
+import Cardano.Ledger.BaseTypes (NonZero, PositiveInterval, nonZero)
 
 import Data.Foldable
 import Data.Function ((&))
@@ -304,6 +305,60 @@ pIntroducedInConwayPParams =
     <*> convertToLedger id (optional pDRepActivity)
     <*> convertToLedger id (optional pMinFeeRefScriptCostPerByte)
 
+pIntroducedInDijkstraPParams :: Parser (IntroducedInDijkstraPParams ledgerera)
+pIntroducedInDijkstraPParams =
+  IntroducedInDijkstraPParams
+    <$> convertToLedger id (optional pMaxRefScriptSizePerBlock)
+    <*> convertToLedger id (optional pMaxRefScriptSizePerTx)
+    <*> convertToLedger id (optional pRefScriptCostStride)
+    <*> convertToLedger id (optional pRefScriptCostMultiplier)
+
+pMaxRefScriptSizePerBlock :: Parser Word32
+pMaxRefScriptSizePerBlock =
+  Opt.option integralReader $
+    mconcat
+      [ Opt.long "max-ref-script-size-per-block"
+      , Opt.metavar "WORD32"
+      , Opt.help "Maximum total size of reference scripts per block."
+      ]
+
+pMaxRefScriptSizePerTx :: Parser Word32
+pMaxRefScriptSizePerTx =
+  Opt.option integralReader $
+    mconcat
+      [ Opt.long "max-ref-script-size-per-tx"
+      , Opt.metavar "WORD32"
+      , Opt.help "Maximum total size of reference scripts per transaction."
+      ]
+
+pRefScriptCostStride :: Parser (NonZero Word32)
+pRefScriptCostStride =
+  Opt.option
+    (integralReader >>= maybe (fail "ref-script-cost-stride must be non-zero") pure . nonZero)
+    $ mconcat
+      [ Opt.long "ref-script-cost-stride"
+      , Opt.metavar "WORD32"
+      , Opt.help "Reference script cost stride (non-zero) for fee calculation."
+      ]
+
+pRefScriptCostMultiplier :: Parser PositiveInterval
+pRefScriptCostMultiplier =
+  Opt.option (readRational >>= toPositiveInterval) $
+    mconcat
+      [ Opt.long "ref-script-cost-multiplier"
+      , Opt.metavar "RATIONAL"
+      , Opt.help "Reference script cost multiplier for fee calculation."
+      ]
+
+toPositiveInterval :: Rational -> Opt.ReadM PositiveInterval
+toPositiveInterval r =
+  maybe
+    ( Opt.readerError $
+        "expected a positive rational with numerator and denominator fitting in 64 bits, got: " <> show r
+    )
+    pure
+    $ L.boundRational r
+
 -- Not necessary in Conway era onwards
 pProtocolParametersUpdateGenesisKeys :: Parser [VerificationKeyFile In]
 pProtocolParametersUpdateGenesisKeys = some pGenesisVerificationKeyFile
@@ -348,8 +403,12 @@ pGovActionProtocolParametersUpdate = \case
       <*> pIntroducedInBabbagePParams
       <*> pIntroducedInConwayPParams
   ShelleyBasedEraDijkstra ->
-    -- TODO: Dijkstra
-    error "pGovActionProtocolParametersUpdate: Dijkstra era not supported yet"
+    DijkstraEraBasedProtocolParametersUpdate
+      <$> pCommonProtocolParameters
+      <*> pAlonzoOnwardsPParams
+      <*> pIntroducedInBabbagePParams
+      <*> pIntroducedInConwayPParams
+      <*> pIntroducedInDijkstraPParams
 
 pGovernanceActionTreasuryWithdrawalCmd
   :: Exp.IsEra era => Maybe (Parser (Cmd.GovernanceActionCmds era))
diff --git a/cardano-cli/src/Cardano/CLI/EraBased/Governance/Actions/Run.hs b/cardano-cli/src/Cardano/CLI/EraBased/Governance/Actions/Run.hs
index 266c4ab3bb..4214d838cc 100644
--- a/cardano-cli/src/Cardano/CLI/EraBased/Governance/Actions/Run.hs
+++ b/cardano-cli/src/Cardano/CLI/EraBased/Governance/Actions/Run.hs
@@ -373,15 +373,9 @@ addCostModelsToEraBasedProtocolParametersUpdate
     ConwayEraBasedProtocolParametersUpdate common (aOn{alCostModels = SJust cmdls}) inB inC
 addCostModelsToEraBasedProtocolParametersUpdate
   AlonzoEraOnwardsDijkstra
-  _
-  _ =
-    -- TODO: Dijkstra
-    -- Add new protocol parameters from
-    -- https://github.com/IntersectMBO/cardano-ledger/blob/master/eras/dijkstra/src/Cardano/Ledger/Dijkstra/PParams.hs#L75
-    -- to
-    -- https://github.com/IntersectMBO/cardano-api/blob/master/cardano-api/src/Cardano/Api/ProtocolParameters.hs#L190
-    -- and remove this `error`
-    error "addCostModelsToEraBasedProtocolParametersUpdate: Dijkstra not supported yet"
+  cmdls
+  (DijkstraEraBasedProtocolParametersUpdate common aOn inB inC inD) =
+    DijkstraEraBasedProtocolParametersUpdate common (aOn{alCostModels = SJust cmdls}) inB inC inD
 
 runGovernanceActionTreasuryWithdrawalCmd
   :: forall era e