diff --git a/models/repo.go b/models/repo.go
index 329e63cc4..c807916dd 100644
--- a/models/repo.go
+++ b/models/repo.go
@@ -1086,7 +1086,7 @@ func CreateRepository(ctx DBContext, doer, u *User, repo *Repository, overwriteO
 			units = append(units, RepoUnit{
 				RepoID: repo.ID,
 				Type:   tp,
-				Config: &PullRequestsConfig{AllowMerge: true, AllowRebase: true, AllowRebaseMerge: true, AllowSquash: true},
+				Config: &PullRequestsConfig{AllowMerge: true, AllowRebase: true, AllowRebaseMerge: true, AllowSquash: true, DefaultMergeStyle: MergeStyleMerge},
 			})
 		} else {
 			units = append(units, RepoUnit{
diff --git a/models/repo_unit.go b/models/repo_unit.go
index 7702697ff..1d54579a6 100644
--- a/models/repo_unit.go
+++ b/models/repo_unit.go
@@ -102,6 +102,7 @@ type PullRequestsConfig struct {
 	AllowSquash               bool
 	AllowManualMerge          bool
 	AutodetectManualMerge     bool
+	DefaultMergeStyle         MergeStyle
 }
 
 // FromDB fills up a PullRequestsConfig from serialized format.
@@ -125,6 +126,15 @@ func (cfg *PullRequestsConfig) IsMergeStyleAllowed(mergeStyle MergeStyle) bool {
 		mergeStyle == MergeStyleManuallyMerged && cfg.AllowManualMerge
 }
 
+// GetDefaultMergeStyle returns the default merge style for this pull request
+func (cfg *PullRequestsConfig) GetDefaultMergeStyle() MergeStyle {
+	if len(cfg.DefaultMergeStyle) != 0 {
+		return cfg.DefaultMergeStyle
+	}
+
+	return MergeStyleMerge
+}
+
 // AllowedMergeStyleCount returns the total count of allowed merge styles for the PullRequestsConfig
 func (cfg *PullRequestsConfig) AllowedMergeStyleCount() int {
 	count := 0
diff --git a/modules/convert/repository.go b/modules/convert/repository.go
index 813201ca6..63a22bb04 100644
--- a/modules/convert/repository.go
+++ b/modules/convert/repository.go
@@ -71,6 +71,7 @@ func innerToRepo(repo *models.Repository, mode models.AccessMode, isParent bool)
 	allowRebase := false
 	allowRebaseMerge := false
 	allowSquash := false
+	defaultMergeStyle := models.MergeStyleMerge
 	if unit, err := repo.GetUnit(models.UnitTypePullRequests); err == nil {
 		config := unit.PullRequestsConfig()
 		hasPullRequests = true
@@ -79,6 +80,7 @@ func innerToRepo(repo *models.Repository, mode models.AccessMode, isParent bool)
 		allowRebase = config.AllowRebase
 		allowRebaseMerge = config.AllowRebaseMerge
 		allowSquash = config.AllowSquash
+		defaultMergeStyle = config.GetDefaultMergeStyle()
 	}
 	hasProjects := false
 	if _, err := repo.GetUnit(models.UnitTypeProjects); err == nil {
@@ -139,6 +141,7 @@ func innerToRepo(repo *models.Repository, mode models.AccessMode, isParent bool)
 		AllowRebase:               allowRebase,
 		AllowRebaseMerge:          allowRebaseMerge,
 		AllowSquash:               allowSquash,
+		DefaultMergeStyle:         string(defaultMergeStyle),
 		AvatarURL:                 repo.AvatarLink(),
 		Internal:                  !repo.IsPrivate && repo.Owner.Visibility == api.VisibleTypePrivate,
 		MirrorInterval:            mirrorInterval,
diff --git a/modules/forms/repo_form.go b/modules/forms/repo_form.go
index 6c7c9bea1..d9eb06d19 100644
--- a/modules/forms/repo_form.go
+++ b/modules/forms/repo_form.go
@@ -140,6 +140,7 @@ type RepoSettingForm struct {
 	PullsAllowRebaseMerge                 bool
 	PullsAllowSquash                      bool
 	PullsAllowManualMerge                 bool
+	PullsDefaultMergeStyle                string
 	EnableAutodetectManualMerge           bool
 	EnableTimetracker                     bool
 	AllowOnlyContributorsToTrackTime      bool
diff --git a/modules/structs/repo.go b/modules/structs/repo.go
index c47700cd0..c23bd1033 100644
--- a/modules/structs/repo.go
+++ b/modules/structs/repo.go
@@ -89,6 +89,7 @@ type Repository struct {
 	AllowRebase               bool             `json:"allow_rebase"`
 	AllowRebaseMerge          bool             `json:"allow_rebase_explicit"`
 	AllowSquash               bool             `json:"allow_squash_merge"`
+	DefaultMergeStyle         string           `json:"default_merge_style"`
 	AvatarURL                 string           `json:"avatar_url"`
 	Internal                  bool             `json:"internal"`
 	MirrorInterval            string           `json:"mirror_interval"`
@@ -171,6 +172,8 @@ type EditRepoOption struct {
 	AllowManualMerge *bool `json:"allow_manual_merge,omitempty"`
 	// either `true` to enable AutodetectManualMerge, or `false` to prevent it. `has_pull_requests` must be `true`, Note: In some special cases, misjudgments can occur.
 	AutodetectManualMerge *bool `json:"autodetect_manual_merge,omitempty"`
+	// set to a merge style to be used by this repository: "merge", "rebase", "rebase-merge", or "squash". `has_pull_requests` must be `true`.
+	DefaultMergeStyle *string `json:"default_merge_style,omitempty"`
 	// set to `true` to archive this repository.
 	Archived *bool `json:"archived,omitempty"`
 	// set to a string like `8h30m0s` to set the mirror interval time
diff --git a/options/locale/locale_en-US.ini b/options/locale/locale_en-US.ini
index e679e1e87..3a8783930 100644
--- a/options/locale/locale_en-US.ini
+++ b/options/locale/locale_en-US.ini
@@ -1791,6 +1791,7 @@ settings.block_on_official_review_requests_desc = Merging will not be possible w
 settings.block_outdated_branch = Block merge if pull request is outdated
 settings.block_outdated_branch_desc = Merging will not be possible when head branch is behind base branch.
 settings.default_branch_desc = Select a default repository branch for pull requests and code commits:
+settings.default_merge_style_desc = Default merge style for pull requests:
 settings.choose_branch = Choose a branch…
 settings.no_protected_branch = There are no protected branches.
 settings.edit_protected_branch = Edit
diff --git a/routers/api/v1/repo/repo.go b/routers/api/v1/repo/repo.go
index b7ed2951a..c422feb04 100644
--- a/routers/api/v1/repo/repo.go
+++ b/routers/api/v1/repo/repo.go
@@ -731,6 +731,7 @@ func updateRepoUnits(ctx *context.APIContext, opts api.EditRepoOption) error {
 					AllowSquash:               true,
 					AllowManualMerge:          true,
 					AutodetectManualMerge:     false,
+					DefaultMergeStyle:         models.MergeStyleMerge,
 				}
 			} else {
 				config = unit.PullRequestsConfig()
@@ -757,6 +758,9 @@ func updateRepoUnits(ctx *context.APIContext, opts api.EditRepoOption) error {
 			if opts.AutodetectManualMerge != nil {
 				config.AutodetectManualMerge = *opts.AutodetectManualMerge
 			}
+			if opts.DefaultMergeStyle != nil {
+				config.DefaultMergeStyle = models.MergeStyle(*opts.DefaultMergeStyle)
+			}
 
 			units = append(units, models.RepoUnit{
 				RepoID: repo.ID,
diff --git a/routers/repo/issue.go b/routers/repo/issue.go
index 15459cd0e..c2969ca4b 100644
--- a/routers/repo/issue.go
+++ b/routers/repo/issue.go
@@ -1484,7 +1484,10 @@ func ViewIssue(ctx *context.Context) {
 		// Check correct values and select default
 		if ms, ok := ctx.Data["MergeStyle"].(models.MergeStyle); !ok ||
 			!prConfig.IsMergeStyleAllowed(ms) {
-			if prConfig.AllowMerge {
+			defaultMergeStyle := prConfig.GetDefaultMergeStyle()
+			if prConfig.IsMergeStyleAllowed(defaultMergeStyle) && !ok {
+				ctx.Data["MergeStyle"] = defaultMergeStyle
+			} else if prConfig.AllowMerge {
 				ctx.Data["MergeStyle"] = models.MergeStyleMerge
 			} else if prConfig.AllowRebase {
 				ctx.Data["MergeStyle"] = models.MergeStyleRebase
diff --git a/routers/repo/setting.go b/routers/repo/setting.go
index dc14b69b3..8349164d4 100644
--- a/routers/repo/setting.go
+++ b/routers/repo/setting.go
@@ -322,6 +322,7 @@ func SettingsPost(ctx *context.Context) {
 					AllowSquash:               form.PullsAllowSquash,
 					AllowManualMerge:          form.PullsAllowManualMerge,
 					AutodetectManualMerge:     form.EnableAutodetectManualMerge,
+					DefaultMergeStyle:         models.MergeStyle(form.PullsDefaultMergeStyle),
 				},
 			})
 		} else if !models.UnitTypePullRequests.UnitGlobalDisabled() {
diff --git a/templates/repo/settings/options.tmpl b/templates/repo/settings/options.tmpl
index f944eb8d8..514a2f5c0 100644
--- a/templates/repo/settings/options.tmpl
+++ b/templates/repo/settings/options.tmpl
@@ -346,6 +346,39 @@
 								<label>{{.i18n.Tr "repo.settings.pulls.enable_autodetect_manual_merge"}}</label>
 							</div>
 						</div>
+						<div class="field">
+							<p>
+								{{.i18n.Tr "repo.settings.default_merge_style_desc"}}
+							</p>
+							<div class="ui dropdown selection" tabindex="0">
+								<select name="pulls_default_merge_style">
+									<option value="merge" {{if or (not $pullRequestEnabled) (eq $prUnit.PullRequestsConfig.DefaultMergeStyle "merge")}}selected{{end}}>{{.i18n.Tr "repo.pulls.merge_pull_request"}}</option>
+									<option value="rebase" {{if or (not $pullRequestEnabled) (eq $prUnit.PullRequestsConfig.DefaultMergeStyle "rebase")}}selected{{end}}>{{.i18n.Tr "repo.pulls.rebase_merge_pull_request"}}</option>
+									<option value="rebase-merge" {{if or (not $pullRequestEnabled) (eq $prUnit.PullRequestsConfig.DefaultMergeStyle "rebase-merge")}}selected{{end}}>{{.i18n.Tr "repo.pulls.rebase_merge_commit_pull_request"}}</option>
+									<option value="squash" {{if or (not $pullRequestEnabled) (eq $prUnit.PullRequestsConfig.DefaultMergeStyle "squash")}}selected{{end}}>{{.i18n.Tr "repo.pulls.squash_merge_pull_request"}}</option>
+								</select>{{svg "octicon-triangle-down" 14 "dropdown icon"}}
+								<div class="default text">
+									{{if (eq $prUnit.PullRequestsConfig.DefaultMergeStyle "merge")}}
+										{{.i18n.Tr "repo.pulls.merge_pull_request"}}
+									{{end}}
+									{{if (eq $prUnit.PullRequestsConfig.DefaultMergeStyle "rebase")}}
+										{{.i18n.Tr "repo.pulls.rebase_merge_pull_request"}}
+									{{end}}
+									{{if (eq $prUnit.PullRequestsConfig.DefaultMergeStyle "rebase-merge")}}
+										{{.i18n.Tr "repo.pulls.rebase_merge_commit_pull_request"}}
+									{{end}}
+									{{if (eq $prUnit.PullRequestsConfig.DefaultMergeStyle "squash")}}
+										{{.i18n.Tr "repo.pulls.squash_merge_pull_request"}}
+									{{end}}
+								</div>
+								<div class="menu transition hidden" tabindex="-1" style="display: block !important;">
+									<div class="item" data-value="merge">{{.i18n.Tr "repo.pulls.merge_pull_request"}}</div>
+									<div class="item" data-value="rebase">{{.i18n.Tr "repo.pulls.rebase_merge_pull_request"}}</div>
+									<div class="item" data-value="rebase-merge">{{.i18n.Tr "repo.pulls.rebase_merge_commit_pull_request"}}</div>
+									<div class="item" data-value="squash">{{.i18n.Tr "repo.pulls.squash_merge_pull_request"}}</div>
+								</div>
+							</div>
+						</div>
 					</div>
 				{{end}}
 
diff --git a/templates/swagger/v1_json.tmpl b/templates/swagger/v1_json.tmpl
index d44583b81..120d02095 100644
--- a/templates/swagger/v1_json.tmpl
+++ b/templates/swagger/v1_json.tmpl
@@ -13626,6 +13626,11 @@
           "type": "string",
           "x-go-name": "DefaultBranch"
         },
+        "default_merge_style": {
+          "description": "set to a merge style to be used by this repository: \"merge\", \"rebase\", \"rebase-merge\", or \"squash\". `has_pull_requests` must be `true`.",
+          "type": "string",
+          "x-go-name": "DefaultMergeStyle"
+        },
         "description": {
           "description": "a short description of the repository.",
           "type": "string",
@@ -15676,6 +15681,10 @@
           "type": "string",
           "x-go-name": "DefaultBranch"
         },
+        "default_merge_style": {
+          "type": "string",
+          "x-go-name": "DefaultMergeStyle"
+        },
         "description": {
           "type": "string",
           "x-go-name": "Description"