Rob Reiner and Michele Singer Reiner were honored at Sunday's Los Angeles Dodgers game ... and their son, Jake, and daughter, Romy, threw out the ceremonial first pitches.

Jake and Romy walked out to the mound in their custom "Reiner" Dodgers jerseys ... and they hugged after throwing their baseballs.

Rob, a lifelong Dodgers fan, was honored before the game in an emotional tribute.

Jake had previously written in a heartbreaking post that he and and his father shared love of the Dodgers -- and he wouldn't be able to set foot in Dodger Stadium without thinking about him -- so this was definitely a fitting way to honor his memory.

The tribute comes months after Rob and Michelle were stabbed to death in their home. Jake and Romy's brother, Nick, has been charged with their brutal murder.

In Jake's post from April, he writes that he's heartbroken and furious ... saying his parents must've been terrified in their final moments.

He explained the devastating loss is especially difficult to process, considering his brother is "at the center of it." Nick's next court appearance is scheduled for September.

On the field, the Dodgers lost to the Boston Red Sox, 8-4.