diff --git a/tree/dataframe/inc/ROOT/RDF/ActionHelpers.hxx b/tree/dataframe/inc/ROOT/RDF/ActionHelpers.hxx
index deb3507d8491e..e385160f75e86 100644
--- a/tree/dataframe/inc/ROOT/RDF/ActionHelpers.hxx
+++ b/tree/dataframe/inc/ROOT/RDF/ActionHelpers.hxx
@@ -58,6 +58,7 @@
 #include <vector>
 #include <iomanip>
 #include <numeric> // std::accumulate in MeanHelper
+#include <optional> // std::optional<int> in SetBranchesHelper
 
 /// \cond HIDDEN_SYMBOLS
 
@@ -1397,7 +1398,7 @@ void SetBranchesHelper(TTree *inputTree, TTree &outputTree, const std::string &i
 /// `branchAddress`) so we can intercept changes in the address of the input branch and tell the output branch.
 template <typename T>
 void SetBranchesHelper(TTree *inputTree, TTree &outputTree, const std::string &inName, const std::string &outName,
-                       TBranch *&branch, void *&branchAddress, RVec<T> *ab, RBranchSet &outputBranches, bool isDefine)
+                       TBranch *&branch, void *&branchAddress, RVec<T> *ab, RBranchSet &outputBranches, bool isDefine, const std::optional<int> &basketSize)
 {
    TBranch *inputBranch = nullptr;
    if (inputTree) {
@@ -1407,6 +1408,8 @@ void SetBranchesHelper(TTree *inputTree, TTree &outputTree, const std::string &i
    }
    auto *outputBranch = outputBranches.Get(outName);
 
+   bool isNewBranch = isDefine || !inputBranch;    // Determine if this is a new branch or not (Created via Define).
+
    // if no backing input branch, we must write out an RVec
    bool mustWriteRVec = (inputBranch == nullptr || isDefine);
    // otherwise, if input branch is TClonesArray, must write out an RVec
@@ -1435,6 +1438,10 @@ void SetBranchesHelper(TTree *inputTree, TTree &outputTree, const std::string &i
          outputBranch->SetObject(ab);
       } else {
          auto *b = outputTree.Branch(outName.c_str(), ab);
+         // Set Custom basket size for new branches.
+         if(isNewBranch && basketSize.has_value()){
+            b->SetBasketSize(basketSize.value());
+         }
          outputBranches.Insert(outName, b);
       }
       return;
@@ -1462,6 +1469,7 @@ void SetBranchesHelper(TTree *inputTree, TTree &outputTree, const std::string &i
          // added to the output tree yet. However, the size leaf has to be available for the creation of the array
          // branch to be successful. So we create the size leaf here.
          const auto sizeTypeStr = TypeName2ROOTTypeName(sizeLeaf->GetTypeName());
+         // Use Original basket size for Existing Branches.
          const auto sizeBufSize = sizeLeaf->GetBranch()->GetBasketSize();
          // The null branch address is a placeholder. It will be set when SetBranchesHelper is called for `sizeLeafName`
          auto *sizeBranch = outputTree.Branch(sizeLeafName.c_str(), (void *)nullptr,
@@ -1478,7 +1486,9 @@ void SetBranchesHelper(TTree *inputTree, TTree &outputTree, const std::string &i
                  bname);
       } else {
          const auto leaflist = std::string(bname) + "[" + sizeLeafName + "]/" + rootbtype;
-         outputBranch = outputTree.Branch(outName.c_str(), dataPtr, leaflist.c_str());
+         //Use original basket size for existing branches and new basket size for new branches
+         const auto branchBufSize = isNewBranch && basketSize.has_value() ? basketSize.value() : inputBranch->GetBasketSize();
+         outputBranch = outputTree.Branch(outName.c_str(), dataPtr, leaflist.c_str(), branchBufSize);
          outputBranch->SetTitle(inputBranch->GetTitle());
          outputBranches.Insert(outName, outputBranch);
          branch = outputBranch;
@@ -1578,7 +1588,7 @@ public:
    {
       // create branches in output tree
       int expander[] = {(SetBranchesHelper(fInputTree, *fOutputTree, fInputBranchNames[S], fOutputBranchNames[S],
-                                           fBranches[S], fBranchAddresses[S], &values, fOutputBranches, fIsDefine[S]),
+                                           fBranches[S], fBranchAddresses[S], &values, fOutputBranches, fIsDefine[S], fOptions.fBasketSize),
                          0)...,
                         0};
       fOutputBranches.AssertNoNullBranchAddresses();
@@ -1779,7 +1789,7 @@ public:
       // hack to call TTree::Branch on all variadic template arguments
       int expander[] = {(SetBranchesHelper(fInputTrees[slot], *fOutputTrees[slot], fInputBranchNames[S],
                                            fOutputBranchNames[S], fBranches[slot][S], fBranchAddresses[slot][S],
-                                           &values, fOutputBranches[slot], fIsDefine[S]),
+                                           &values, fOutputBranches[slot], fIsDefine[S], fOptions.fBasketSize),
                          0)...,
                         0};
       fOutputBranches[slot].AssertNoNullBranchAddresses();
diff --git a/tree/dataframe/inc/ROOT/RSnapshotOptions.hxx b/tree/dataframe/inc/ROOT/RSnapshotOptions.hxx
index 97318ef8a6da1..c1d21d9389d4a 100644
--- a/tree/dataframe/inc/ROOT/RSnapshotOptions.hxx
+++ b/tree/dataframe/inc/ROOT/RSnapshotOptions.hxx
@@ -14,6 +14,7 @@
 #include <Compression.h>
 #include <string_view>
 #include <string>
+#include <optional>
 
 namespace ROOT {
 
@@ -25,7 +26,7 @@ struct RSnapshotOptions {
    RSnapshotOptions(const RSnapshotOptions &) = default;
    RSnapshotOptions(RSnapshotOptions &&) = default;
    RSnapshotOptions(std::string_view mode, ECAlgo comprAlgo, int comprLevel, int autoFlush, int splitLevel, bool lazy,
-                    bool overwriteIfExists = false, bool vector2RVec = true)
+                    bool overwriteIfExists = false, bool vector2RVec = true, const std::optional<int> &basketSize = std::nullopt)
       : fMode(mode),
         fCompressionAlgorithm(comprAlgo),
         fCompressionLevel{comprLevel},
@@ -33,7 +34,8 @@ struct RSnapshotOptions {
         fSplitLevel(splitLevel),
         fLazy(lazy),
         fOverwriteIfExists(overwriteIfExists),
-        fVector2RVec(vector2RVec)
+        fVector2RVec(vector2RVec),
+        fBasketSize(basketSize)
    {
    }
    std::string fMode = "RECREATE"; ///< Mode of creation of output file
@@ -45,6 +47,7 @@ struct RSnapshotOptions {
    bool fLazy = false;                              ///< Do not start the event loop when Snapshot is called
    bool fOverwriteIfExists = false; ///< If fMode is "UPDATE", overwrite object in output file if it already exists
    bool fVector2RVec = true;        ///< If set to true will convert std::vector columns to RVec when saving to disk
+   std::optional<int> fBasketSize {};         /// Set a custom basket size option. For more details, see https://root.cern/manual/trees/#baskets-clusters-and-the-tree-header
 };
 } // namespace RDF
 } // namespace ROOT