Huddersfield manager Mark Robins this week warned Lennon that striker Vaughan was not for sale after Lennon watched his team play twice in four days.
But the Celtic manager remained coy when asked about the 25-year-old former Everton and Norwich forward, who has scored 12 goals for the Sky Bet Championship side this season.
"I've been watching a lot of players," said Lennon, whose team face Motherwell in the Scottish Premiership at Fir Park on Friday night.
"I'm not here to talk about one specific player. There were 22 players at Huddersfield-Burnley and 22 players at Bolton-Huddersfield. Maybe I wasn't specifically looking at James Vaughan.
"I've been linked with him and that's fine, people are putting two and two together.
"I have spoken to Mark Robins, I know Mark from my playing days. So it's not just James Vaughan I'm looking at but he is a player we think is a good player."
Lennon endured a largely frustrating summer transfer window until a final flurry, when the likes of Teemu Pukki and Nir Biton joined his earlier signings.
But, of all Lennon's summer signings, only Virgil van Dijk established himself as a regular starter in time for Celtic's Champions League campaign and Lennon wants to give players a better chance of settling in.
"The January window is more difficult - clubs don't want to part with players," he said.
"But we are looking to bring maybe one or two players in with the view of bedding them in between January and July for obviously, if we win the league, for the qualifiers in July and August just to bed them in to the way we play.
"The close season is so short and with some of the players being away at the World Cup, it will be even shorter this year."
One extra player who will be available for Lennon in January is Mo Bangura, whose loan club Elfsborg have confirmed they will not make an offer for his services on a permanent basis.
Lennon said: "He is still involved in the Europa League and we are planning to give him a bit of time off. He has been playing for almost a year. He is due to report back in at the start of next year.
"It's up to Mo, we will see what sort of condition he is in and what sort of form he is in.
"In the early part of his loan spell at Elfsborg he was doing very, very well so we will see if the loan has given him that match experience that he needed."
Bangura was booed on his most recent trip to Celtic Park after playing for Elfsborg in the Champions League qualifiers against Lennon's wishes.
But Lennon said: "That's not really Mo's fault. I didn't think he should play but I think he was under immense pressure from Elfsborg and I certainly don't point any finger of blame at Mo on that one."
Celtic and Motherwell go into the game in hugely contrasting moods with Lennon's side thrashing Hearts 7-0 on Sunday in the William Hill Scottish Cup 24 hours after the Lanarkshire side had been knocked out by Albion Rovers.
But Lennon is only looking ahead.
"It will give Motherwell an extra edge, they have got to restore some pride," he said.
"It was a big shock because they have been so consistent over the last couple of years.
"I remember coaching under Gordon (Strachan) when we beat St Mirren 7-0 and the following weekend we lost 1-0 to them in the cup.
"We are in good form and we want to maintain that but we will come up against a very dogged and determined Motherwell."
Meanwhile, Celtic have a number of illness and injury problems ahead of their Scottish Premiership clash at Motherwell on Friday night.
Tom Rogic (calf), Dylan McGeouch (ankle) and James Forrest (hamstring) are doubts while Georgios Samaras and Nir Biton have both missed training in the last two days with a virus.
Adam Matthews has returned to training following shoulder surgery but will not be involved while Beram Kayal (foot) and Steven Mouyokolo (Achilles) remain out.
Provisional squad: Forster, Ambrose, Lustig, Fisher, Izaguirre, Van Dijk, Brown, Ledley, Mulgrew, Commons, Stokes, Boerrigter, Pukki, Balde, Biton, Rogic, McGeouch, Forrest, Samaras, Zaluska.