diff --git a/modules/plugins/lsp/presets/default.nix b/modules/plugins/lsp/presets/default.nix
index abd8346d..bb3ce502 100644
--- a/modules/plugins/lsp/presets/default.nix
+++ b/modules/plugins/lsp/presets/default.nix
@@ -40,6 +40,7 @@
     ./nushell.nix
     ./ocaml-lsp.nix
     ./ols.nix
+    ./omnisharp.nix
     ./openscad-lsp.nix
     ./phan.nix
     ./phpactor.nix
diff --git a/modules/plugins/lsp/presets/omnisharp.nix b/modules/plugins/lsp/presets/omnisharp.nix
new file mode 100644
index 00000000..7ddd4b48
--- /dev/null
+++ b/modules/plugins/lsp/presets/omnisharp.nix
@@ -0,0 +1,98 @@
+{
+  config,
+  lib,
+  pkgs,
+  ...
+}: let
+  inherit (lib.meta) getExe;
+  inherit (lib.modules) mkIf;
+  inherit (lib.nvim.types) mkLspPresetEnableOption;
+  inherit (lib.generators) mkLuaInline;
+
+  cfg = config.vim.lsp.presets.omnisharp;
+in {
+  # HACK: this server should be named `omnisharp-roslyn`, but the extension `omnisharp-extended-lsp-nvim` only works if it is named `omnisharp`
+  options.vim.lsp.presets.omnisharp = {
+    enable = mkLspPresetEnableOption "omnisharp" "OmniSharp Roslyn" [];
+  };
+
+  config = mkIf cfg.enable {
+    vim.lsp.servers.omnisharp = {
+      cmd = mkLuaInline ''
+        {
+          '${getExe pkgs.omnisharp-roslyn}',
+          '-z', -- https://github.com/OmniSharp/omnisharp-vscode/pull/4300
+          '--hostPID',
+          tostring(vim.fn.getpid()),
+          'DotNet:enablePackageRestore=false',
+          '--encoding',
+          'utf-8',
+          '--languageserver',
+        }
+      '';
+      root_dir = mkLuaInline ''
+        function(bufnr, on_dir)
+            local fname = vim.api.nvim_buf_get_name(bufnr)
+            on_dir(
+              util.root_pattern '*.slnx'(fname)
+                or util.root_pattern '*.sln'(fname)
+                or util.root_pattern '*.csproj'(fname)
+                or util.root_pattern 'omnisharp.json'(fname)
+                or util.root_pattern 'function.json'(fname)
+            )
+          end
+      '';
+      init_options = {};
+      capabilities = {
+        workspace = {
+          workspaceFolders = false; # https://github.com/OmniSharp/omnisharp-roslyn/issues/909
+        };
+      };
+      settings = {
+        FormattingOptions = {
+          # Enables support for reading code style, naming convention and analyzer
+          # settings from .editorconfig.
+          EnableEditorConfigSupport = true;
+          # Specifies whether 'using' directives should be grouped and sorted during
+          # document formatting.
+          OrganizeImports = null;
+        };
+        MsBuild = {
+          # If true, MSBuild project system will only load projects for files that
+          # were opened in the editor. This setting is useful for big C# codebases
+          # and allows for faster initialization of code navigation features only
+          # for projects that are relevant to code that is being edited. With this
+          # setting enabled OmniSharp may load fewer projects and may thus display
+          # incomplete reference lists for symbols.
+          LoadProjectsOnDemand = null;
+        };
+        RoslynExtensionsOptions = {
+          # Enables support for roslyn analyzers, code fixes and rulesets.
+          EnableAnalyzersSupport = null;
+          # Enables support for showing unimported types and unimported extension
+          # methods in completion lists. When committed, the appropriate using
+          # directive will be added at the top of the current file. This option can
+          # have a negative impact on initial completion responsiveness;
+          # particularly for the first few completion sessions after opening a
+          # solution.
+          EnableImportCompletion = null;
+          # Only run analyzers against open files when 'enableRoslynAnalyzers' is
+          # true
+          AnalyzeOpenDocumentsOnly = null;
+          # Enables the possibility to see the code in external nuget dependencies
+          EnableDecompilationSupport = null;
+        };
+        RenameOptions = {
+          RenameInComments = null;
+          RenameOverloads = null;
+          RenameInStrings = null;
+        };
+        Sdk = {
+          # Specifies whether to include preview versions of the .NET SDK when
+          # determining which version to use for project loading.
+          IncludePrereleases = true;
+        };
+      };
+    };
+  };
+}